I always encourage individuals to use vector format graphics as they are smaller in size, have higher quality, and don't lose resolution over time.
One of the main challenges in creating vector graphics (SVG, EMF, PS, etc.) is the software available to create these graphics.
You can use InkScape which is free to create illustrations and export as graphics format. You can also use Adobe Illustrator which is not free to do the same. However, the challenge with this software may be the time it takes to learn and get used to the different options and features of each.
One of the more commonly used software across the board may be Microsoft PowerPoint, which many depending on work or school affiliations have free access to the latest version of. Since this software is more commonly used and people already know how to do basic things, it seems reasonable and efficient to use it for diagram generation for your reports and manuscripts or other uses.
Here is a short video that walks you through the steps taken to go from a raster image diagram to its vector twin and export it in vector format and then use it in Word to compare the qualities.