In music-making, "compression" means narrowing the dynamic range of audio signal content. Usually it is used to make instruments and mixes sound louder. https://en.wikipedia.org/wiki/Dynamic_range_compression
When talking about data compression, it means making the amount of stored and transferred data smaller. Sound files can be data-compressed, and then we talk about methods and file formats like MP3 and FLAC compression. It's supposed to sound the same, but take up less data storage spage and be faster to transfer over networks. For images, you've probably seen things like JPEG and PNG. For general data files, you may have seen the name ZIP. These formats are about data compression as well. https://en.wikipedia.org/wiki/Data_compression
When you upload music to internet services, you'll most likely want to use audio data compression of some sort, often MP3, instead of sending raw uncompressed files over the internet. MP3 and other audio data compression methods can reduce the amount of transferred and stored data a lot. A data reduction of 90% is common. Uncompressed, a minute of "CD quality" stereo music takes around 10 megabytes, but with MP3 or other audio data compression methods it can be on the order of 1 megabyte, depending on the exact method and quality settings.