The first thing you should take into account is that Pinterest allows image, link, and video-type posts. The character limit for your pin's description should be under 500 characters, including links and hashtags.
Due to API (integration with third-party apps) limitations, you will need a Pinterest Business account to post videos. You can see how to easily convert your account to Business here.
Sum up
Text Posts: No
Max. characters: 500
Hashtag Limit: No
Image Posts: Yes
Multi-Image Posts: No
Link Posts: Yes
Link Editing: No
Video Posts: Yes (Business accounts only)
Mentions: No