I did a task to write an email to my friend with asking for advice.

The problem is that my new friend Sasha getis upset with her new job in Morschihinskaya.

She got this job because of me and it is the reason because, which is why I care about thise situation.

You could also say, "...and that is the reason why I care about the situation."

I met Sasha inat the last volunteers' camp in Kenozero National Park.

After the camp I went to Morschihinskaya village to work there as visit centre administrator for a one month.

IThat was my plan.

I invited Sasha with me because the park also needed also a guide for one month here in Morschihinskaya.

But she saitold me that she had a plan to start to find somea normal job in Moscow.

You can say "told me" (no preposition) or "said to me" (which needs the preposition "to"), but "told me" sounds best here. It would also sound find to leave out "me" and just say "But she said that she had a plan...."

And she thinks that now she just spendwastes her time withon this job for a small salary.

"Spends time" is neutral. You can say "I love my job, so I spend a lot of time at work every day" or "I hate my job, but I have to spend a lot of time at work every day." It's like проводить время, I think. "Waste time" is always negative, like "тратить время." (Sorry for any Russian mistakes!) To me, "waste time" makes more sense here, since your friend is unhappy with the job.

Due to it was my invitation to goBecause I invited her to come here.

You could use "due" if you said "due to the fact that I invited her to come here."
If you want to emphasize that you were the one who invited her, you could say, "Because I was the one who invited her to come here."

What cando you recommend methat I do?

Or just "What do you recommend?"
"What do you think I should do?" would also fit this context.

I did a task to write'm writing an email to my friend withand am asking for advice.

CPlease check it for mistakes please!

Hi, Arseniy!

HI hope you’re okay.

"Hope you're okay" can be spoken but, in writing, it's very casual.

The problem is that my new friend Sasha getis upset with her new job in Morschihinskaya.

She got this job because of me and it is the reason becauseso that's why I care about thisher situation.

I met Sasha in theour last volunteers' camp in Kenozero National Park.

After the camp I went to Morschihinskaya vVillage to work thereas as visitor centre administrator for a mone moth.

IThat was my plan.

I invited Sasha to go with me because the park also needed also a guide for onea month here in Morschihinskaya.

She works as a guide and she is very good inat it.

But sShe said meto me, however, that she had a plans to start to find some normallooking for a regular job in Moscow.

And sShe thinks that now she just spends her time with thisshe spends too much time on her current job for such a small salary.

I feel some guilt for herguilty.

Due to it wasShe's here because of my invitation to go here.

What can you recommend me?

WPlease write soon and tell me all of your news!

I did a task to write email to my friend with asking for advice.

She got this job because of me and it is the reason because.This is why I care about this situation.

After the camp I went to Morschihinskaya village to work there as visit centre administrator for a mone moth.

I invited Sasha with me because the park needed also a guide for one moth here in Morschihinskaya.

But she said me that she had a plan to start to find some normal job in Moscow.

And now she thinks that now she just spends her time with this jobshe works for small salary.

I feel some guilt for her.guilty

Due to it was my invitationthis, i decided to go there.