What service do you use to store/write/edit project documentation?

Question

Project management

Hello.
In general, there is design documentation for a large project, we are doing it with several people.
We use git, trello and bitrix24 (yes, yes, you have to deal with masochism)
What service can you recommend for the trello type?
It is very convenient for splitting the application into modules and so on.
The customer wants to rent an office for us, and that we use local services (such as on the intranet). He is afraid that his idea will be taken away or leaked. We signed a couple of non-disclosure agreements with him, on liability, etc. (everything is serious about this in Canada).

Answer 1

We use products from Atlassian - Jira and Wiki. Jira - for project management and bug control, Wiki - for storing related documentation, database schemas and all that sort of thing. Moreover, we have set up automatic creation of tickets in Jira by phone call or e-mail of the client. I, unfortunately, do not know the technical details of the implementation, but it's cool.
Jira, in my opinion, is also good because in it the entire structure and logic of transitions and changes in ticket states can be easily customized to your needs right in the system, and it is available both from the workplace and on the road (even from home, you can, if an attack of workaholism tormented).
We are also quite strict with security, the processing of personal data and all that, but no one objects to the cloud and this does not raise security issues.
We, however, for the sake of security, store the sources in a local repository.

Answer 2

trackstudio.com ?

Answer 3

Microsoft Word + Onedrive/GoogleDrive/Dropbox. Any document is written in review mode so that any edits can be seen. We break into files, modules, and write. Then we combine. No masochism.