Exporting

File>Export>Export As

Select jpg and art boards at bottom

Jpg options maximum

Other various export options of the supported file formats.

https://helpx.adobe.com/illustrator/using/exporting-artwork.html

Save As:

If your document contains more than one artboard and you want to save to a previous version of Illustrator, you can choose to save each artboard as a separate file or combine the content from all artboards into a single file.

https://helpx.adobe.com/illustrator/using/saving-artwork.html