I have a maple tree (only a few inches tall) and I was wondering how you are supposed to shape the trunk. I wanted to make it have a bit larger trunk but taper into a smaller point at the top. could someone tell me techniques to use or what to use to do so?

Hello and welcome.
You are basically asking for a “how to bonsai” which is quite impossible to type here. There are too many variables ( your knowledge being only one of them)
In short there are a few ways to get where you want: the grow and chop technique ( faster but leaves big scars), or the slower grow and prune technique ( slower but less scars)
As I said, it all depends on a lot of variables.

If it is just a seedling you need to grow it for several years before you can do anything with it. Let it grow unchecked do not prune or wire just let it grow.

I only needed was a small amount of info. In which you have provided. All I have to do is search for how to do the techniques and that will help. thank you.

I accidentally did a comparison study last year and found that seedlings that got a lot of sun grew taller and thicker.

I dug up several maple seedlings from the north side of the house and put them in pots on the south side, with full sun 6-8 hours. By September they were 20-30 cm tall, 6-10 mm thick, while some still in the ground in the shade were 10 cm tall and 2 mm thick.

Southside also got fertilizer, so there were more variables, but the big one was full sun.

Ivan wrote:

I accidentally did a comparison study last year and found that seedlings that got a lot of sun grew taller and thicker.

I dug up several maple seedlings from the north side of the house and put them in pots on the south side, with full sun 6-8 hours. By September they were 20-30 cm tall, 6-10 mm thick, while some still in the ground in the shade were 10 cm tall and 2 mm thick.

Southside also got fertilizer, so there were more variables, but the big one was full sun.

This is a great study, I wonder how was this received.

I didn't do it on purpose, and never wrote anything up, but I was somewhat impressed by the fact that the ones in the sun grew so much.

Typically we have one seedling that grew well and make too much generalization from that. In this there were 11 in the sun and 4 in the shade, and I think I can generalize from that.