I struggle with this kind of passages

My native language isn't english so I will just explain it with an example. Also the word "passage" probably isn't right for this situation, but anyway, hope you will understand it. My problem is: Let's say I go C to G, or G to A, F to C ... There are many examples. I mean I need to use my same finger in 2 different strings (not at same time) But I just can't move my finger easily. How people do that? And is there any particular name for this technique? I searched it on internet couldn't find any result