Looking on the internet deeply has found these results:

I am writing to iform you is the most popular phrase on the web.

I wite to inform you 1237,000 results on the web	I am writing to iform you 1363,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	"Dear Mr. Waters..."I am writing to thank you for your electronic correspondence. I am the agent of General Toda I am writing to you in that capacity. Dear Joe, I am writing to you because I can't get hold of John. I am writing to inform you of my problems here in Cuba... ...and to ask for your help. I am writing to you on a silver platter, your freedom. On behalf of the Alumni Giving Fund, I am writing to you to ask... I am writing to you a few minutes before I escape. I am writing to the command of Tripoli.

I wite to inform you

1237,000 results on the web

I am writing to iform you

1363,000 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

"Dear Mr. Waters..."I am writing to thank you for your electronic correspondence.
I am the agent of General Toda I am writing to you in that capacity.
Dear Joe, I am writing to you because I can't get hold of John.
I am writing to inform you of my problems here in Cuba... ...and to ask for your help.
I am writing to you on a silver platter, your freedom.
On behalf of the Alumni Giving Fund, I am writing to you to ask...
I am writing to you a few minutes before I escape.
I am writing to the command of Tripoli.