Have (got) to 用来表示客观的必须，可能是规则、规定、法律条例等。

You have to pay tax.
你必须交税。

We have to check everyone's ID.
我们必须检查每个人的身份证。
ID 身份证，身份证明（identification的缩写）

Have to 的 have 是实义动词，现在时态要变疑问句需要助动词 do 或 does，变否定句需要 don't 或 doesn't：
Do you have to vote in an election?
你必须在选举中投票吗？
vote 动词，投票，表决
election 名词，选举

He doesn't have to wear a uniform to school.
他上学不必穿制服。
uniform 制服