The module docs are here - https://docs.blesta.com/display/dev/Modules
And, all modules that ship with Blesta are open, so they serve as good examples. I'd look at one that's most similar to what you're trying to accomplish.
You can use Blesta for anything, I use it for selling licenses, a client of ours used Blesta for renting office space. For employers to post jobs, etc you could do this but you will need a custom Plugin / Module to do it. I recommend ModulesBakery (we use Mujahed for all our plugins / modules).
Thanks for the CORE-1803.
This can be a good addition , i have resolved this by changing the name widget to "Proformas / Invoices" not a professional solution but accepted solution that we can live with it
.
If, for example, the service gets canceled it cannot be reactivated. So can a client order a package more than once in certain scenarios, such as if it is no longer active or if it is canceled?
This sounds normal. Splitting a ticket does not also change it's ticket status. Since it is currently open, it would stay open after it was split.
I think you received that error because you changed the ticket status to the same status that it currently was. Because the status is not changing, the ticket does not need to be updated, and does not log any details about the status change, hence the error.
See CORE-1803.
Since you and your clients find "Invoice Number" confusing for pro forma invoices, do you also suggest separating pro forma invoices and regular invoices from the list of invoices in the client/admin UI shown on the client profile?
as serge say , Europe this latest years are fighting fraud , and they are very strict in their accountability .
let imagine , your clients receive a proforma that is containing some incorrect words (legally) , and they claim at the fiscal authority , be sure you are a bad situation .