No real difference, one is more of an imperative ‘call him’ while one is often used in suggestions ‘(why don’t you) give him a call’. Ultimately they’re pretty much interchangeable.

you can use both expressions as Michaela suggests. You can say this in regards to talking on the telephone, but also 'call him' can also be used if you want someone to shout out to another person who may be a bit further away.

There is no difference in meaning or in use Gl