I basically agree with SoltBegins, but let me state it a different way.
To "give effect to" something is to make it work, to make it carry out its desired intent.
To "effect" something (as a verb) is to bring it into existence or make it happen.
So if you said, "Mr Smith effected an agreement between the parties", that would mean that Smith managed to convince the parties to come to some compromise. Like, he convinced them that they should each pay half the cost. If you said, "Mr Smith gave effect to the agreement between the parties", that would mean that he did something to make the agreement actually happen, like he collected the money from each of them.
Addendum
To try to answer your question:
By "make it happen" here I mean something along the lines of "bring it into existence". Maybe it would have been more clear if I'd just left it at "bring it into existence".
"Give effect to" specifically means to cause something that previously existed only as an idea or on paper to actually happen. We routinely talk about "giving effect to a contract" or "giving effect to the new law".
To "effect" simply means to cause, or cause to exist. Sometimes, often, causing something to exist and making it happen are the same thing. When we say "Smith effected X" we often mean that he both caused it to exist and caused it to produce the desired outcome. If, for example, you say "I effected an update to the document", making the update exist and making it actually change the document are probably a single event, you can't separate them out. So in a given case,
whether "to effect X" means to create a concept that is not yet actually happening in the real world,
or if it means both to create the concept and to really make it happen, depends on the context.
In the case of an agreement, if all the parties are truly willing it might be that once the agreement is made, they all go off and do whatever, and no one thinks of a separate step of giving effect to the agreement. It just depends on context.
Where're you going for your holiday(s)?
Where're you going on vacation/holiday?
You normally use the preposition "on", but the use of the "for" isn't ungrammatical.
As for the sentence "Tell me a good place to go on holiday", there's nothing with it grammatically.
Best Answer
You're confusing two different things here. What do we do? is an interrogative sentence asking what course of action one should proceed with. The first do is one of those so-called auxiliary verbs in English that are used to form questions. The second do is nothing more than the main verb of the sentence. For example:
what we do, on the other hand, is a non-question statement—a noun clause, as Cardinal aptly pointed out in the comments section. It can only be properly understood as part of a larger context. In your case, where two organizations are telling you information about themselves, it simply means the following: this is what our sphere of activity is, this is what we specialize in or this is what our job is. The verb to do is commonly used to ask people questions about their jobs:
You would say what we do on your website and then describe what exactly your job is to let visitors to your website know what you can offer them.