Captures in the authorizations depend on a Global configuration of the system. The instructions to configure the capture of a transaction can be found in this link.
After the transaction is made and authorized, the capture will be performed automatically according to the time configured.
To capture funds in your VTEX store follow these steps:
Login to your store's Admin
Then go to Menu -> Orders -> Orders Management -> All orders
Search for the order you want to capture.
Once inside the order the invoice is created, and this will proceed to capture the funds.