Can I give the smaller agents who sell through me their own login with a credit limit so they can book without calling me?

Yes, in most cases you can. A travel portal can be set up with a sub agent layer, where each agent you work with gets their own username and password and signs in to a version of your portal that carries your branding. They search, they book, and the booking lands in your system under their name, so you can see at any time who sold what. This saves you from taking every request by phone or message and retyping it yourself.

On top of that you can usually control what each agent sees and pays. You can set a different markup for one agent or for a whole group of agents, so your better producing agents get a sharper rate, and you can give each one a credit limit or a prepaid wallet balance. When they book, the amount is taken off their balance, and once they reach their limit the system stops them booking until they top up or you release more credit. Statements of what each agent has booked and what they still owe are normally part of the same screen.

I should be honest about the limits. Whether the sub agent module is included depends on your plan, so it is worth confirming before you promise logins to anyone. The supplier behind the booking does not know your agents exist, which means you stay responsible for paying the supplier even if an agent has not paid you yet. Offline top ups, such as a bank transfer, also usually need someone on your side to confirm the money arrived before the credit shows.

Check whether your plan includes the sub agent portal, and ask how credit limits, top ups and agent statements are handled, before you start signing up agents.