Mentafy needs access to the Word document on the user’s MS Onedrive cloud storage in order to access the automatically saved version history.
For security reasons, by default the users will not be able to grant this permission themselves, unless the administrator has configured this in general for all apps or for Mentafy specifically.
This special link will grant all Microsoft permissions Mentafy ever requires (full Mentafy and import - users will not get prompted to accept the permissions request individually): https://login.microsoftonline.com/organizations/adminconsent?client_id=cb89aab0-b687-4d59-9699-36ec76abbd4b - click “Accept”:

N.B.: The user with administrator privileges can also grant fewer permissions for the whole organization while giving them for herself ("Consent on behalf of your organization" checkbox) during the process. In case only finished documents will be imported the required permissions are limited to:

Go to User Consent Settings in Azure [https://portal.azure.com/#view/Microsoft_AAD_IAM/ConsentPoliciesMenuBlade/~/UserSettings]
Choose a Consent Policy Option
Define Required Permissions [https://portal.azure.com/#view/Microsoft_AAD_IAM/ConsentPoliciesMenuBlade/~/Permissions]
You can create a free personal Microsoft account and use it with Mentafy. In this scenario the users can grant permissions as required on their own behalf.