While many video games have a strategic element, some use this as the central point of the play. This can be organising armies before heading in for an offensive, planting a farm to generate the best crops, planning a network of roads or laying out an amusement park.
Strategy games have in common the focus on making premeditated decisions to gain the outcome you need. Some games like Civilization do this by providing the player with all the information they need. Other games, like Kingdom Two Crowns force the player to make a strategic decision on limited knowledge.
These games are further divided between those that are turn-based and allow the player as much time as they need to make decisions, or real-time where you have to make decisions with limited delay. Some strategy games, like Disintegration put you right in the action, so you are fighting in the ranks of your forces as well as commanding oversight.
Finally, you find strategy gameplay in a lesser way in competitive games like Fortnite. This is strategy on the go, so you have to make snap decisions about whether to go on the offensive or retreat.