Backend Programming

Hello, I would need a backend programming for my website. The backend must have the following functions: - I must be able to create customers with name, address, e-mail etc. and the allocation of which subscription package was purchased. - In the best case, I can create the subscription packages myself in the backend. There is no pay function etc. required. - I have to be able to upload the invoices for each individual customer. This means that the customer has a menu item "Invoices" in his login, which is subdivided by month and date. - Contact requests received from the website should also be visible in the backend. - Nevertheless there should be a registration form, which I can switch on & off in the best case. In this registration form the personal data as well as a checkbox (mandatory field) for the acceptance of the data protection regulations must be present. If I create the customer from the backend, he should receive a link to the registration confirmation when clicking on an extra button, where he can then set his password. & the checkbox for the data protection regulations should also be available here. It is important that clicking on the checkbox in the backend is visible for each individual customer. - The customer can register or log in. Forgot password Function. - The customer can view his invoices in his backend and download them as PDF files. - The customer can see his active subscription. - The customer has the possibility to send tickets via an internal ticket system. It is important that it is built without WordPress or similar. The website itself is programmed without CMS. The backend should also be built in this way.