Can I control what each of my staff can see on the portal, like hiding my cost prices and my profit from them?

Yes, you can decide what each member of your staff can see and do on the portal, including keeping your supplier cost and your profit hidden from them.

Most travel agency software works on roles. You create a login for each person and put them into a role, and that role decides which parts of the system open up for them. A booking agent might be able to search, hold and issue, while only you and your accounts person can see the supplier cost, the margin on each booking, the markup rules and the reports that show total profit. The same idea covers who is allowed to cancel a booking, who can process a refund and who can change the settings on the website, because those are the actions that hurt the most if the wrong person does them by mistake.

How finely you can slice it does depend on the system and on the plan you are on. Some setups give you a few ready made roles, such as agent, accounts, manager and owner, and you simply pick one for each person. Others let you tick individual permissions one by one, and even tie a user to a single branch or a single group of sub agents. It is worth being honest with yourself about the size of your team, because a system that only offers two or three fixed roles will feel tight once you have several people working different jobs.

Before you commit, ask to see the user and role screen on a live demo, create a test staff login for yourself, then sign in as that person and check that the cost price and the profit reports really are out of sight.