Over the years I have gotten used to the following sentences formation:
I know that this is the website but how do I specify for what I am
paying?
Instead of:
I know that this is the website but how do I specify for what am I
paying?
I want to ask which of the following is correct and is it possible for them both to be correct, one being more formal or something?
I also want to ask what the general rule for such cases is?
Best Answer
I am assuming the intended meaning is that the question is "how do I specify {the identity of the thing, for which I am paying}" (rather than "how do I specify {what I am giving as payment}").
Neither of the options presented reads as correct English to me. The "For what I am paying" or "For what am I paying" object clauses are both awkwardly constructed, and it seems to me that they were arranged this way purely to avoid ending them in "for".
Use of 'to specify'
The second possibility is that it's a mistaken use of "for" with the verb to specify. Specify is a transitive verb - it takes an object - so there is no need to use "for" to indicate what is being specified:
Proposed Answer:
The way that I would word this is as follows:
Despite the repeated claims to the contrary, it is perfectly acceptable for an English sentence to end in a "preposition", and in this example it is the most natural construction. It is also totally acceptable to use this in a formal context.
Whatever you do, please don't tie your sentence in a knot just to avoid ending with "for".