The document you posted states that it is an
Entry Permit - New - Tourist Visa
Since you are going to be entering in Sharjah, I consulted the site of Sharjah Airport.
I also consulted the right hand side of the document you posted.
1- Entry permit (Visit): validity (60) days from date of issue.
(a) Long stay visit for 90 days not extendable. (b) Short stay visit for (30) days not extendable.
5- Entry permit (Tourism): validity (60) days from date of issue - duration of stay (30) days from day of entry and extendable on time for a similar period.
One of the above apply to you.
Whichever of the above applies to you, the follow is certain:
- 60 days after the date of issue is the latest you can enter Sharjah
- At the very least you have 30 days after entering the country to leave i.e. you should leave on the 30th day at the latest
- Upon entering Sharjah, you can enquire about whether you can extend your stay for an additional 30 days (as per point 5)