Create and use multiple signatures in Gmail Getting started.  

To create multiple signatures, in Gmail, click on this link to see Google Support instructions: 

https://support.google.com/a/users/answer/9259758?hl=en 

Additionally, you can click on this link to view a how-to video: 

https://1.bp.blogspot.com/-KXba5D_5MDs/XmflzXX98QI/AAAAAAAAIwY/GeXXmg_o768wlJpYiC7sRQp-ji0bMAnSwCLcBGAsYHQ/s1600/069-GSP-Multiple-Signatures-FrontCardonly-R4-AV.gif