There are several ways/places to apply passwords. Here are the most common
2:
You can apply a database password that users must supply when opening the
file.
(File must be open exclusively to make this change. Open Access
File>Open>Browse to file>click arrow on the "Open" button in the File
Dialog and select "Open Exclusive")
Then, in Access UI: Tools>Security>Unset Database Password: supply current
password
You can apply a password that would prevent changes to Code (and to
forms/reports that have code attached).
In the VBE: Tools>Properties>Protection: uncheck "Lock Project for viewing".
optionally, delete password.
A password can also be required by incorporating User-Level security, but
that's a major undertaking so I'm guessing that isn't what you did (and I'm
not familiar enough with it to tell you how to undo it...)