In Baldur's Gate 3, Shar's chosen mission is to start the normal plot first. Later, you can directly follow Shadowheart to the ancient temple to trigger this mission.
After entering the mission, proceed with the plot as normal. In Chapter 2, take Shadow Heart to the ancient temple and then trigger Shar'er's Chosen Mission.
Shar can be found at the top of the map in Chapter 2. You can find it quickly by following the main line guide.
It’s quite good to be able to successfully participate in the corresponding electorate tasks after arriving at the ancient temple.
Shar, the Night Girl, is a neutral evil upper god with long black hair and purple eyes.