Audacity is a good place to start. If you use it, please consider reviewing the Audacity Workflow thread stickied at the top of the forum. There are plenty of other software options if you wish to consider them: Sony Sound Forge, Steinberg WaveLab, Magix Samplitude, and many others, including apps for Mac. Check the stickied "Where do I find (insert software here)?" thread for links to a broad range of software that many in our hobby find useful for a variety of activities.
As for removing crowd noises, clapping, and "everything like that", the approach taken depends in part on the situation specifics. In general, removing crowd noises while the music's playing playing is difficult, though some have
experienced success with iZotope RX. Reducing between-song clapping to levels even with or quieter than the music, or reducing the dynamic range (i.e. making the quiet parts louder relative to the loud parts / the louder parts quieter relative to the quiet parts) typically involves: compression, limiting, and / or a volume envelope. Try a search in this forum on one or more of those terms for more details on what they are, how they work, and how to use them. Good luck, ask away with additional questions, and welcome to TS!