Password not filling on IOS

I use an iPhoneX. The Avast password app is installed and synced across several other devices using the Master Password. All pw info appears on the Password app on my iPhone. When I use an app or website the password are often saved to the IOS “Accounts and Password” function rather than the Avast App. And when I use an app or website, it appears to go to the IOS “Accounts and Password” location rather than the Avast Password App. Most times I have to go the the Avast app and manually use the copy function to get userid and pw info onto a login page

Anyone have a similar experience? Any help available?