Hi @Anandu 

Please have a look at the guides.

https://helpcenter.veeam.com/docs/vbo365/guide/vbo_required_permissions.html?ver=50

If you choose to add the organization as modern app only, you need a global admin to create the Azure App registration. The required Permissions for the Azure AD are documented here.

If you choose to add Modern App with legacy permissions enabled, you need a global admin to configure the app registration and a backup Account with the following Admin roles:

• Exchange Online
• Sharepoint Admin 
• Teams Administrator

@Mildur is spot on here, the only value add I’d also suggest is, if you’re not sure between Basic Auth and Modern auth, this KB article lists the limitations with modern auth:

KB3146: Considerations and limitations when using different authentication methods (veeam.com)

Good luck!

Both @Mildur and @MicoolPaul have given the right info here.  Be sure to read the KB on the different auth types as it can be a bit confusing.