Terms of Service
Terms of Service (TOS) pages act as a legal contract between the company (you) who owns the website and mobile app and its users who have access to your sites and mobile app. Possessing a TOS agreement is optional since there is no law asking you to have that.
In general, one of the main reasons you find TOS critical for your site is to inform customers that they are not in your sites, which are exposed to the bad behaviors of the Internet such as viruses or negative comments. Additionally, you are able to refer to the TOS if customers are trying to start an argument with you.
Take note that almost legitimate gateway’s payments will command you to issue the TOS on your site. If not, you will not be approved.