You could ask all the main political parties for a copy of their manifesto or other literature explaining what they think. As there are hundreds of political parties it is OK to focus on the main ones, although important to explain that there are many more. If someone is interested you could help them find out more about these.
You could help someone to access the websites of all the main political parties, or the ones they are interested in.
If there is an election due you can contact the council for a list of all the candidates standing in the election in that area. You could then support someone to find and look at literature from all of these candidates.
You could help someone to decide who they want to vote for by drawing up a list of the things that matter most to that person. You could then look at all the information you have received before an election to see what each of the candidates or political parties say about these things. This might help someone come to a decision, however, each individual must always make up her or his own mind about who they want to vote for.