Google Docs doesn’t directly have a way to create image captions in their program, however there are several ways to create this effect fairly easily with the tools available already in Google Docs.

1. Begin by inserting and sizing your image to an appropriate size and shape for the document that you are working on.
2. Next go to the Insert Menu and choose Drawing and New.
3. In the drawing insert a text box that contains the text for the the caption that you want to add, make sure that you format it and have it set the way you want it before exiting since you wont be able to do back and change it once you exit.
4. Place the caption below the image and center the caption on the image.
5. Select the image by clicking on it and click on the Format menu, then choose the Text Wrap for the Wrapping option.
6. Repeat this process for the figure, this will allow the text to wrap around image and the caption.