Yes!!

Mobile:

1) Log out of tumblr

2) on the login page of the app, there should be an option for “Forgot my password”

3) click on that and you can change your password! It’s pretty self explanatory from there

Desktop: You can either do the “Forgot my password” way, or:

1) On the top right of your tumblr, there should be a small human figure

2) when you click on that, it should show all your blogs, the blog you’re currently on, and a small bar showing your activity. And Blog settings

3) Click on blog settings, and there should be an option to change your password!!

Sorry if i got anything wrong!!