One letter makes all the difference:

Advice is a noun. Change the ‘c’ to an ‘s’ and you have advise which is a verb and pronounced slightly differently:

‘I really value your advice and your opinion is important to me.’ noun

‘Please can you advise me, as I am unsure what to do for the best.’ verb

Hint for remembering the difference: ‘ice’ is a noun, so advice is a noun too; ‘is’ is a verb, so advise is a verb too.