Parts of the Mosaic Law were ceremonial and parts were moral. The Ten Commandments were part of the moral law and we still must obey them.
Christians also have ceremonial law and moral law.
Ceremonial law usually refers to the regulations governing the “ceremonies” established by the Church to carry out a moral law (eg. to honor God and keep holy the Lord’s day; other actions and/or sacraments commanded by Christ).
The following example may help.
*Moral Law *= Love the Lord Your God; Keep holy the Lord’s Day;
*Ceremonial Law *= words and actions to be followed by priest and people in the celebration of the Mass. Type of priestly vestments to be worn. Regulations regarding various vessels used. Type of music.
Ceremonial Law can change. Also the laws can vary in different parts of the world/different cultures.
Sometimes it can be difficult to distinguish whether something is ceremonial or moral. For example, with the Sacraments. The words we use to baptize are part of the ceremony, yet they were commanded by Jesus, so we are not free to change them (Mt 28:19 "…baptizing them in the name of the Father, and of the Son, and of the Holy Spirit).
If you have any particular laws in mind, it might be easier if you stated them and then someone could let you know whether it is a moral or a ceremonial law.
By the way, Catholics have a “moral” responsibility to be obedient to Church ceremonial regulations!