When I'd like to specify dates to do some task, how can I express that the last date should be included in the provided period?
From 5th to 7th March
Meaning March 5th, March 6th and March 7th.
The least ambiguous would be to use "up to and including":
From the 5th up to and including the 7th of March
Using through works as well:
From the 5th through the 7th of March
since that word means
4 c : to and including
// Monday through Friday
(source: Merriam Webster)