Can I add bookings I arranged offline, over the phone or by email, into the same system as my website bookings?

Yes, in most travel agency software you can enter a booking you arranged yourself and keep it next to the ones that came through your website. It is usually called an offline or manual booking. You fill in the details by hand, the passenger name, the travel dates, the supplier, what you paid and what you are charging, and once it is saved it behaves like any other booking, so it shows in your booking list, in your reports and on that customer's file.

The thing to be clear about is that a manual booking is only a record. The system is not connected to the airline or the hotel for it, so it cannot issue the ticket, send a live voucher or cancel anything on your behalf. If the supplier changes the timing or your customer wants to cancel, you go back to the supplier the way you always did, then update the record yourself so your figures stay right.

How much you can do here depends on your plan and on how your portal has been set up. Some setups let you add every kind of product by hand, flights, hotels, transfers and packages, while others allow only a few, and many let you decide which staff members are allowed to create or edit a manual booking.

The thing worth checking is whether manual bookings feed into your sales reports and your accounting the same way online bookings do, because that decides whether you end up with one true picture of the business or two separate ones.