I need an app or whatever to like take sound and cancel out background noise like if someone is talking and the fan noise is in the way I want to take out the fan noise and streetcar noise and only have the voice please help.
Most audio editing applications have noise removal/reduction features, and there are some available as third-party plug-ins.
Audacity is free, and has a noise reduction function in "effects". It works ok, there are better ways, but it is free. Every decent paid audio app has the feature as well. It's even built into some video editors like Final Cut, where it can be fairly automatic, but there are still adjustments you can do.
Free or paid, video or audio only, the principle that all of them use is you select a portion of your recording that has only the noise you want to get rid of. You use that as a "noise print", and the software develops a rather sophisticated digital filter that acts to remove that noise. There are controls that let you control how aggressive the noise reduction is. For the more automatic ones, like FCP, you don't necessarily choose the noise-only selection, it takes a "guess" at what the noise is you're trying to ditch and develops a digital filter for it.
There are always trade-offs. Because the digital noise filter is not a fixed filter but changes dynamically, it can be surprisingly effective, but at a cost. The more the noise occupies the same frequency range as your desired audio the more difficult it is to get rid of. Some types of noise are easier to filter than others. Fan noise is one of the worst, so be prepared to compromise. Streetcar noise is pretty bad too. Some noise reduction plug-ins have more tweaks that let you control how it works, how much noise reduction you like, and let you dial-in the compromise between noise and side-effects.
There are also single-ended noise reduction filters that don't adapt to the specific noise, but rather apply either a broadband noise gate or a multiband noise gate or expander to audio. This is a much older method, first pioneered by
Richard Burwen in the early 1970s as an analog product, is effective for low level noise like tape hiss or record surface noise, but cannot deal with the higher noise levels found in location audio.
Side-effects of today's digital noise reduction, buy the way, sound a lot like low quality mp3 compression. The more NR you do, the more swishy and ringy things get. So you have to listen carefully, and when you get the noise reduced the way you like, back off a bit. It's human nature to try to do too much with EQ and noise reduction. At an extreme, you can virtually eliminate the noise, but the remaining audio is so badly beat up you wouldn't want to use it that way, so you dial back in a little less noise reduction (more noise) and reach a compromise.