How to use Obliged?

I'm not sure that "obliged" is the word you are looking for.

I would be very grateful if...

or

I'm very appreciative of...

Can you please provide more context?

PS - A more lucid way to ask your question:

Does "I'm highly obliged" need to be at the beginning of a letter, or should it be later, after mentioning the requirement.

"Obliged" is usually used when delivering bad news. It means you are, or will be, forced to do something the other person won't like. Example: "If you do not pay your outstanding balance within the next five days, we will be obliged to freeze your account."

The older, less-used meaning is one of "obligation" (its root word), which is where the phrase, "Much obliged" comes from. But, a

Much Obliged has always meant that you were thankful or appreciative of something