You can share a Google Doc (to include Docs, Sheets, and Slides) by right-clicking on the doc in your Google Drive and selecting "Share… Share…"
Either method above makes the "Share with others" dialog box:
The simplest and most straightforward way to share the doc is to start typing the name of the person with which you want to share the doc. By default, the doc will be shared with an editing privilege, unless you want a different setting:
Commenting is a handy way to hold a discussion on a document, and viewing is for letting people see, but not edit or comment. Keep in mind that all three sharing privilege settings will allow the recipient to make a copy of the doc that they will own and have full editing rights.
Note the "Notify people via email" checkbox on the lower right is checked by default. That will general an email message to your recipient(s) with a link to the Google Doc you are sharing. If you uncheck that box, they will have to look in their "Shared with Me" section of their Google Drive.
Want to explore more options for sharing? Click the "Get shareable link" feature in the upper right of the "Share with others" and then the little disclosure triangle to the left of "Copy link:"
If you discover a useful feature or process, be sure to share it in the comments below.