Draw.io (https://www.draw.io/) is an online charting tool. You can make all kinds of tables / charts / graphs / flowcharts / venn diagrams, etc. for business, engineering, software, networks and more. It lets you create any number of professional images, giving you full control over them. You can save your images as jpg, pdf or png. It also allows you to save your work on your desktop, or a cloud storage service of your choice i.e. google drive, one drive, dropbox, etc. You have the option to download the desktop app with the same functionality and create enchanting looking diagrams and use them in your documents and presentations.
Best of all, the service is entirely free. You have the option to contribute though, in various ways, and if you like the service, I think you should!