**1. Introduction**

As one of the essential elements of the modern world economy and the increasing use of advanced information and communication technology (ICT), technological changes have driven fundamental changes in the economic and social environments, thereby transforming society from the industrial into the information age [1]. The increasing use of ICT has significantly changed the way we live, learn, and work, transforming the direction of the interaction of people, business systems, and public institutions. The development of information technologies, and in particular, the advancement of Internet technologies, enables existing businesses to progress and the opening of new businesses, leading to the growth of e-business and the digital economy [2,3].

The Internet has contributed to the extremely dynamic development of e-commerce within e-business. In its simplest sense, e-commerce implies the purchase and sale of goods or services online as well as advertising revenue. Without the Internet, e-commerce would be virtually non-existent. Therefore, e-commerce includes all activities of buying and selling products and services that are performed via the Internet or other electronic communication channels [4]. First of all, e-commerce consists of distributing, buying, selling, marketing, and servicing products and services through the Internet. It also incorporates electronic money transfer, supply chain management, e-marketing, electronic data exchange, and automated data collection systems [5]. Over time, e-commerce has transformed from a mechanism for online retail sales into something much broader [6]. This is why it is of great importance which e-commerce strategy the company will choose to implement [7]. The selection of an optimal strategy is vital because the strategy defines the future direction and actions of the organization or part of the organization [8]. Developing an e-commerce strategy requires combining existing approaches to business and developing an information systems strategy. In order to achieve a competitive advantage, it is crucial to join innovative techniques in traditional strategic approaches [9]. The implementation of an adequate strategy may help the company to achieve and maintain its competitive advantage in the long run [10].

Many of the real problems are often characterized by a number of mostly antagonistic criteria. Multiple-criteria decision-making (MCDM) is a notable part of operational research. It considers the issues in which we are faced with a greater number of, most often conflicting, criteria when making a decision [11–13]. The extraordinarily rapid and dynamic development of MCDM worldwide has contributed to a number of MCDM methods and techniques proposed by scholars to solve a wide variety of problems [14,15]. Some of the prominent methods that are most applied are the AHP method (Analytic hierarchy process) [16], the ELECTRE method (Elimination et choix traduisant la realité) [17], the PROMETHEE method (Preference ranking organization method for enrichment evaluations) [18], the TOPSIS method (Technique for order preference by similarity to ideal solution) [19], the COPRAS method (Complex proportional assessment of alternatives) [20], the VIKOR method (Visekriterijumska optimizacija i kompromisno resenje) [21], the MOORA method (Multi-objective optimization on basis of ratio analysis) [22], the MULTIMOORA method (Multi-objective optimization by ratio analysis plus the full multiplicative form) [23], and so on.

Hwang and Yoon [19] develop the TOPSIS method (Technique for Order Preference by Similarity to Ideal Solution). To solve a broader range of problems when problems are related to uncertainties, ambiguities, and vagueness, the TOPSIS method has a proper extension based on the application of fuzzy, intuitionistic, grey, and neutrosophic numbers to be able to cope with these problems. To date, the TOPSIS method has been applied to solving many cases, often in combination with other techniques, some of which are as follows: the application of TOPSIS when deciding on a discipline, course, and university [24]; the application of entropy TOPSIS-F for the performance assessment of green suppliers [25]; the evaluation of solar power technologies based on the application of the intuitionistic fuzzy TOPSIS [26]; hotel evaluation and selection based on the modified TOPSIS decision support algorithm [27]; the evaluation of the sustainable energy planning strategies based on the SWOT-AHP method and Fuzzy TOPSIS method [28]; supplier evaluation and selection based on the green innovation ability based on the BWM and fuzzy TOPSIS [29]; website assessment by employing the interval type-2 fuzzy number TOPSIS approach [30]; assessment in civil engineering [31–33]; evaluation and selection of personnel [34–37]; and so on.

Neutrosophic sets were established by Smarandache [38] to deal with complex DM problems related to uncertainties, which are followed by inconsistent and indeterminate information. The use of the three membership functions in order to express accuracy, indeterminacy, and inaccuracy during the evaluation of alternatives in MCDM can be said to be a very important and significant advantage of neutrosophic sets. So far, neutrosophic sets have been utilized in different fields such as medical analysis [39–42], transport [43,44], information and communication technology [45–47], MCDM [48–52], and so forth.

Therefore, a novel extension of the TOPSIS method adapted for the application of single-valued neutrosophic sets is the subject matter of consideration in this manuscript. The applicability and usability of the developed single-valued neutrosophic TOPSIS extension are demonstrated on a numerical illustration of the evaluation and selection of e-commerce development strategies. For all of the preceding reasons, the remainder of the manuscript is based on the following global organization of sections. The preliminaries are presented in Section 2; in Section 3, the TOPSIS method customized to the use of single-valued neutrosophic numbers (SVNNs) and group decision-making is presented; Section 4 contains a presentation of the numerical clarification, whereas Section 5 presents a discussion and a comparison analysis. Finally, concluding remarks are specified at the end of the manuscript.
