Embassy of Qatar

You cannot enter Qatar at this time unless you are a permenant resident of qatar or a citizen of Qatar

No, but you must wear a mask when visiting.

Yes you can send a letter to the Ambassador of the Embassy. But, depending on what you sent, they might not recieve it due to that if they feel as though the letter or package is suspcious itself, they will check it out first.

Best to contact them directly via email on their website

Police clearance don't need to be from Qatar embassy. You can get the clearance from any police station.

If you are a citizen of Qatar, you do not. You need a Visa for travel anywhere unless you are a citizen of the place your going.

I have Somali passport If I came visit Doha haw I get visa