When using Safari, it is recommended that you disable autofill data and also clear the browsing data.
With the Safari browser open, select Safari
from the top of the screen and select Preferences.

A new window will open. Select the Autofill
tab and if checked, select the Using
information from my contacts and Other
Forms check-boxes to deselect them.

Once completed, close the window.
With the Safari browser open, select Safari
from the top of the screen and then select Preferences.

A
new window will open. Select the Autofill
tab and if checked, select the Using
information from my contacts and Other
Forms check boxes to deselect them.

Within
the Passwords window,
select any specific passwords that require clearing and then click
on the Remove button.
Once complete, close the window.

For more information about managing usernames and passwords with Safari,
refer to the Apple website:
https://support.apple.com/guide/safari/use-autofill-ibrw1103/mac