"The boss wants more coffee."
Translation:Chefen vill ha mer kaffe.
Vill is a mere expression of will. Jag vill simma for example.
Vill ha is for expressing what you want to have. As in the example above.
Does that help?
The meaning of få is much like that of 'receive', but få is a neutral word where 'receive' may sound a bit more formal.
Doesn't sound natural. Also, the sentence does not state that he wants to get coffee, it just says that he wants it, so focus is on his having the coffee, not on the receiving of it.
In informal speech you can use "mera" for uncountable nouns like this one too, but in writing, yes, it's just for plural.
When we use också with Vill ha, it comes between Vill and ha, however here mer follows vill ha. Can someone please explain. Tack så mycket.
också is an adverb so it can go between the verb and its particle. It doesn't have to, we could also have said Chefen vill ha mer kaffe också. There can be a slight difference in meaning between these two versions as to what too refers to.
mer is an adjective in this case, and it needs to go next to the noun it modifies – "mer kaffe" is one sentence constituent.