This letter would appear to have been written by Charles Wesley, son of Samuel Wesley and grandson of Charles Wesley (1707-88). His mother was Charlotte Louise Wesley (born Martin), whom Samuel Wesley had married in 1793.
The letter is a typical child's letter of the early 1800s, containing many polite phrases and written out in Charles's best handwriting. Charles thanks his aunt - probably Sarah Wesley (1759–1828), sister of Samuel Wesley - for a blanket. He also mentions that he has just written to his 'dear Mother'. Clearly, Charles was spending time away from home; perhaps he had just gone to boarding school?