A virtual mailbox is a commercial mail receiving agency. The Postal Service delivers your letters to that shop. The shop scans them, forwards them, or both. Traveling Mailbox, iPostal1, and Anytime Mailbox sell that service. What each one charges, and which streets it uses, is on its own site.
The form
USPS requires a PS Form 1583, Application for Delivery of Mail Through Agent, for each person who receives mail at the agency. The name and address on the form have to match the photo identification and the address identification you show. Those documents have to be current. Spouses each file their own form if both of them receive mail at the same box. When something on the form changes, you file a new one.
What the address is
The Postal Service requires the agency to present the delivery address as a private mailbox, a PMB, not as an ordinary home. That distinction matters. A bank, the IRS, or a state office may refuse a mailbox when a form asks for a residential address. Ask that institution. A mailbox company cannot answer for them.
The box does not replace a visa, a cédula, or an address in Ecuador. It is how a US letter still has somewhere to land. Banking paperwork is in the banking chapter. A phone number is a different problem, in the phone chapter.
Sources: USPS, commercial mail receiving agencies · PS Form 1583-A. Rewritten here.