Simple management software (German) wanted for tour operator in Brazil

I am looking for a software for my travel agency in Brazil, we organize individual tours to the Pantanal & Bonito.

The moment a customer contacts me (usually by e-mail via the contact form on my homepage), I would like to create a customer file.

The software should then perform the following tasks for each customer:

• save all e-mail correspondence
• list all tour suggestions and cost calculations
• remind me of all dates and times (arrival, departure, overnight stays, program of excursions, bookings, payments that I have to make and the customer has to pay me)
• list all bookings to be made and made for hotels, transfers, guides, etc. and remind me when these have to be made
• after the tour, it should be possible to record feedback, comments and remarks and then file them

I would like to have all the information listed above available with one click on the customer name or the travel date and not have to search for it on my PC in various programs and files.

1 to 2 workstations are planned.