what adapter do i need to purchase to connect to a computer monitor. i have a MacBook Air, Mac OS Sierra Version

Hey there!

This depends on the ports of your monitor and your MacBook Air. If you have a newer, USB-C MacBook Air, you can use something like Apple's Digital AV Multimedia Adapter as long as your monitor has a HDMI input (https://www.apple.com/au/shop/product/MUF82ZA/A/usb-c-digital-av-multiport-adapter).

If you have an older MacBook, you can buy third party adapters to connect from your Thunderbolt 2 on your MacBook Air to a HDMI port (https://www.apple.com/au/search/mini-displayport-to-hdmi).

Keep in mind there are different ports for different monitors, so you'll need to check that the adapter you are purchasing has male ports which are compatible with your MacBook Air and female ports which are compatible with your monitor.

Best of luck!

Be sure to properly identify exact build year model of 13-inch MacBook/Air.

• Identify your MacBook Air model - Apple Support

https://support.apple.com/en-us/HT201862

Then you may acquire best proper match of connector cables, adapters, etc.

Various devices & vintages of accessories, displays, should be correct to work.

• Ultimate Mac Lookup by serial number, order/model & EMC number, Model ID @ everymac.com

https://everymac.com/ultimate-mac-lookup/

The original specification information that accompanied the product new

would be helpful to locate the kind & type of ports accessories to match.

Good luck & happy trails!🌞🐝