How do I remove my late wife's Apple Account and replace it with mine on her iPad?

On my late wife's iPad, the account was in her name, but when she passed away in 2018 I have tried several times to remove her account and replace it with mine, but I an still having reminders from Apple to sign into her account, and even though I know I have got the correct password it is still not letting me in, because the reminders are coming up on my computer, instead of the iPad, so can you please tell me how I can get around this, because it is not letting me delete her email address either from the iPad

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