Hi @jasmineorpilla
Has the phone been dropped or gotten wet at all?
''If it hasn't,'' here's a [https://www.youtube.com/watch?v=pXUX-nQp8WE|video] that shows how to replace the display in the phone.
Search online for Realme C3 LCD display to find suppliers that suit you best.
''If it has'' then depending on what has happened there may be more damage in the phone., and until it has been opened and inspected you don't know what may have happened to cause the problem.