You can change the Slug for Documentations page from BetterDocs Settings. To do so, go to your WordPress Dashboard and navigate to wp-admin -> BetterDocs -> Settings. From the ‘General’ tab, you will find the options to change Documentation Page Slug, Category & Tag Slugs as well.
By default, the Doc page slug is set to ‘docs’. You can easily go ahead and give it any name you want. Afterward, make sure to hit the ‘Save Settings‘ Button.