Hey, I need to order my transcripts soon to apply to colleges but I know that my school has letter grades. But some of the universities I’m planning on applying to require percent grades (or else they’ll give you the lowest grade for the letter. B from 89% would be seen as 80%). Is there anyway my school can get me a transcript with my percent grades (given they do have them but do not use them) so I could apply to these schools using them? Pelase advise!
Ask your high school. Which colleges want % grades? I have not heard of those so far. Most high schools use letter grades and most colleges accept them. . Some public systems recalculate GPAs like the U of California System of schools. The reason for that is they do not count grades in physical education, and some other nonacademic classes that may be on your transcript, and they weight grades in AP classes their own way, so U of Cal evens the playing field by recalculating your GPA. Quite a few schools may do that, U of California publishes the formula so you can do the calculation yourself.
Feel free to correct me, but I am unaware of any college where this is the case. As noted, some schools, notably UC, asks you to recalculate GPA.
You can certainly ask your HS. I would not count on them making any change though.
The universities are actually out of country. In many countries out of US most high schools use percent system.
Are high schools able to change in on their account or are they held to policies from the state or district for how transcripts are supposed to be.
That’s a key piece that should have been mentioned from the outset. 
No, most don’t, although I am sure you will find some.
A French student applying to a US university would have a transcript on the 0-20 scale; no US university would ask that the HS conform its transcripts to the US standard. They would either use the HS transcript or ask for the original transcript to be converted and attached to the original transcript. It is likely that an international university would be the same.
It depends upon the HS, which is why you have to ask them. For most US high schools that use an alpha grade, no corresponding numeric grade accompanies it.