You certainly can, but it's not easy to do, so we don't provide our own guide.
Here's a StackExchange question that should help:
I can only share category now, but topic is more specific, so why can't share topic?
@main You can, go into the topic, and click the Heart icon in the first post.
@a_5mith Thanks, it's hard to find, I think watch or like are very different with share, maybe share should be independent.
@main Good web design is being able to do what you want in less than 3 clicks. Click the icon, click your social network of choice. 2 clicks. It's not something people are going to use a lot, despite you wanting them to. So having it visible on every post isn't a wise choice from a UI perspective.
@a_5mith Yes, you're right, in fact I just want 1 click to share, because I think share is the most important way to spread community's influence. Maybe only I think so, I'll change the theme to put all share buttons just shown when mouse roll over
@ozanduman i got too big error while uploading wallpaper
@main Do share how you did that when you do it. I also think sharing icons should be more prominent sometimes. The heart icon really isn't intuitive in my opinion, wish it was more like the share icon on Android or if the share options slid out sideways when hovered over.
@luke Yes, I changed as below, put share icon at the right