You must contact the developer of the Excel app.
In order to do that, you need to go back to where you got it, and look for that information there.
Is 'The Android App Store' a thing?
I have never heard of that appstore, quite possibly because there is more than one- therefore using the word 'The' in the name of it would be a misnomer.
Anyway, I will assume that you are using Google Play Store.
I do not use that appstore for various reasons.
But I will attempt to find it online, without the horrid app called Google Play Store.
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So there is the contact information for the developer.
Good luck with that, as most developers for apps like this seem to ignore most users, but you may be the exception.
You will need to provide the make, model, and Android version of your device, along with the version number of the Excel app.
Tell them exactly what your issue is, as you did here.
To be honest, if you can find an app to do this function from F-Droid, you would be much better off.
Even if you had the same issue, the vast majority of developers associated with F-Droid are much more responsive and helpful than those on the Play Store.