Hi,
If you’re asking about the trigger buttons, here’s the ifixit [guide|3253] guide, that may help.
You can check if the restore spring action is still OK or if the buttons are broken etc.
[https://www.ebay.com.au/itm/234140388711?chn=ps&_ul=AU&_trkparms=ispr%3D1&amdata=enc%3A1fIpu0WHHQsC4jkMaG8buQg51&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=234140388711&targetid=1598233946344&device=c&mktype=pla&googleloc=9070670&poi=&campaignid=14475548384&mkgroupid=132282084371&rlsatarget=pla-1598233946344&abcId=9300653&merchantid=505771275&gclid=EAIaIQobChMIiIe5rbOI9gIViZpmAh27Qgd5EAQYASABEgLQTPD_BwE|Replacements] are available online. (supplier example only). Just search for ''PS3 trigger button parts'' to get results for suppliers that suit you best.