The words practice and practise sound very alike. They definitely have some big differences between them, which is very important for any speaker of English to know. Foremost, you should be aware that English speaking differs across places, and the two most popular sects of English spoken are the American and British English.
Now, the word "practise" only appears in British English, and there is nothing such in American English. The word "practice" exists in both American and British English, and it is used as a noun in both. It describes the act of doing something over and over again so as to master it. It can also be synonymous with a profession in some fields like art and science, such as art practice, medical practice, and more.
So, in American English, the verb form of the word "practice" remains as "practice," which the usage in a sentence would differentiate which part of speech it's representing. But in the case of British English, the verb form of "practice" is "practise."