Today I have a task from my boss that I have to study redmine and tell him if we can import issues excel file to redmine. I don't know anything about redmine. Can we import issues excel file to redmine? And if we can, what I should start from.
Start here: https://github.com/leovitch/redmine_importer/wiki
You can use Excel to export a CSV file, then use the Redmine importer to import the items.
This presumes that your Excel items are reasonably typical, and do not have embedded calculations, images, special fonts, etc.