The word “practice” is a noun, it refers to an act itself, not who is doing it.
Examples using the word “practice” (noun)
1.If you want to speak French well, you need to practice.
2.I’m afraid I’m rather out of practice.
3.It is their practice to give annual raises.
Practise is a verb meaning ‘do something repeatedly to improve one skill’. It is a systematic training by multiple repetitions (rehearsing a behavior or engaging in an activity several times repeatedly) in order to improve or mastering that skill. To put this much simply, practise is a verb (doing word) and practice a noun (thing)
.Examples using the word “practise” (verb)
1.The new government has promised all citizens the right to practise their religion.
2.Why don’t you practise what you preach?
3.I’m quite good at tennis but I need to practise my serve.