What are the free solutions for modern investments?

Question

open source

Hello! Tell me if there are any analog solutions like exchange server + onedrive, yandex, mail.
You need your own service as storage of mail attachments and mail. There is an ekschenzh, but in any case, you also need a license for onedrive. There is something similar. If it's not clear what I mean, here's how

Answer 1

Will it be difficult to raise OwnCloud on your own or not? https://ru.wikipedia.org/wiki/OwnCloud