Why is there no sleep option in Windows 10?

In some cases, Windows 10 Sleep mode missing is caused by incorrect power settings. To get rid of the issue, you should make sure Sleep mode is enabled in the Power options setting. A quick guide for you here: Go to the search box, input control panel and click this app to open it.

Why doesn’t my PC have a sleep option?

Click Start, type Power Options and select same from the list when it appears. On the left pane, click on Choose what the power button does. Then click Change settings that are currently unavailable and go to Shutdown settings section and enable the Sleep and Hibernate check boxes there. Click Save Changes.