The first time, you need to enter the data yourself. If the option to save passwords is on, it will be recorded.

Or are you talking about importing the passwords from another browser? https://support.mozilla.org/en-US/search/advanced?q=%20importing%20the%20passwords%20from%20another%20browser&language=en-US&sortby_documents=relevance&a=1&w=1

edited wrong link

I am an app developer, not a browser guy. I have a client who would like to open web sites and auto fill any user ID and password automatically. I've got the opening working but how do I send login information to Firefox so it will fill in the appropriate boxes?

Hi Roger, if you are developing an external application, I think you will find it tricky to inject text into browser form fields without also creating a browser extension (like Bitwarden, Roboform, etc.) to facilitate interaction with pages.

You also could look into whether any of the automated testing tools could be used in your solution.

These topics are a bit beyond the scope of the support forum:

• Where to go for developer support
• https://discourse.mozilla.org/c/add-ons/35