Is there any specific API to verify/validate the access token in case of Oauth and to verify/validate username and password in case of Basic Auth?

Okay. I don't have any use case to create it outside dam but I trying to make sure to check if it's restricted.

Can we create/upload files in any default/custom folder in /content like in -/content/rep:policy/content/campaigns/content/projects/content/experience-fragments/content/cq:tags/content/usergenerated/content/core-components-examples/content/launches/content/communities/content/sites/content/forms/con...

Thanks Mohit, that helps.Also I saw that content folder can be renamed, which moves the existing data from /content to somewhere else.Just wanted to know where does this data go and how many such content folders can be created?

Can we create sites in these default folders -> /apps, /conf, /etc, /home, /jcr:system, /libs, /oak:index, /rep:policy, /rep:repoPolicy, /system, /tmp, /var in AEM On-Prem?

 Currently I'm using AEM on-prem 6.5, and I see assets as seen in the attached SS. However, can we create any other custom asset than files, collections, shared links, etc.?