Good start. You got the reference arguments right.
First, function needs a return type in its definition, even if it returns nothing. Place the keyword "void" in front of the function name.
Your input statement is wrong on two counts. You have the arrows pointing wrong way (think of them as pointing in the direction of information flow - from cin to the variables.) Also, when doing a multiple input statement, you must use separate arrows for each variable destination.
Do not return 0 from a (now) void function. In fact, void functions do not require a return statement at all.
Do not put a pause in the function (no output other than your prompt belongs there.)
void Get_inputs ( int &a, int &b, int&c)
cout << "Enter three integers " << endl;
cin >> a >> b >> c;