Can someone manage invoices without managing my content?

Give them the Billing Only role in Accounts. Their dashboard shows the selected account, amount owed, monthly plan, next invoice, saved card, and each unpaid invoice with a Pay invoice link. The account menu, at the top of the page and above Sign out, switches between accounts they can access. They also have their own User Profile and Contact / Feedback. They cannot edit websites, content, settings, or team access.

Emailed invoice links work without signing in. If no card is saved, Add a card to continue opens the secure card form, then returns to the invoice to pay. Adding a card does not pay the invoice by itself.