If you are using the default System,User password field, it is disabled for security reasons.
You could capture it in different entity (probably NPE) and set it on the System.User.Password or set some random password and send it to the users email.
As Nirmalkumar Thandavamoorthy said you needs to get password in new entity not in system.user
Is the context entity of the used dataview Account?
If so I would advise you to create a different entity, which you use to collect the information of you anonymous user. Instead of that someone directly is entering data on the account table. This new entity should have two password attributes; password and Confirm password. The save button should trigger a microflow which creates the account, copies the new entity object details to the Account object and sets password if both password values are equal. Attribute type of both password attributes should be string, not HashString. Besides that this attribute type is not editable, if you would be able to enter a value it will be hashed and then again hashed which will give a wrong result.
Long story short