Hi @IniobongNkanga-8038,
In this case, if user B wants to share the folder with User C, then user A will receive the request email.
In this case, if user B wants to share the folder with user C, then user A will be sent a request email.
But I suggest you check the following related settings are correct:
1.First contact your administrator >SharePoint Admin Center >Active sites >Select your site> Settings> External file sharing. Change the option to disable anyone from sharing.
2.Navigate to site >site permission >Change how member can share.
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