The holy days of obligation for Latin Church Catholics are indicated in canon 1246 of the 1983 Code of Canon Law
Can. 1246. §1. Sunday, on which by apostolic tradition the paschal mystery is celebrated, must be observed in the universal Church as the primordial holy day of obligation. The following days must also be observed: the Nativity of our Lord Jesus Christ, the Epiphany, the Ascension, the Body and Blood of Christ, Holy Mary the Mother of God, her Immaculate Conception, her Assumption, Saint Joseph, Saint Peter and Saint Paul the Apostles, and All Saints. §2. With the prior approval of the Apostolic See, however, the conference of bishops can suppress some of the holy days of obligation or transfer them to a Sunday.
Placed in the order of the liturgical calendar, the ten days (apart from Sundays) that this canon mentions are:
8 December: Solemnity of the Immaculate Conception of the Blessed Virgin Mary
25 December: Solemnity of the Nativity of the Lord (Christmas)
1 January: Solemnity of Mary, the Holy Mother of God
6 January: Solemnity of the Epiphany of the Lord
19 March: Solemnity of Saint Joseph, Spouse of the Blessed Virgin Mary
Thursday of the sixth week of Eastertide: Solemnity of the Ascension of the Lord
Thursday after Trinity Sunday: Solemnity of the Most Holy Body and Blood of Christ (Feast of Corpus Christi)
29 June: Solemnity of Saints Peter and Paul, Apostles
15 August: Solemnity of the Assumption of the Blessed Virgin Mary
1 November: Solemnity of All Saints
The number of holy days of obligation was once much greater. With the motu proprio of 2 July 1911, Supremi disciplinae, Pope Pius X reduced the number of such non-Sunday holy days from 36 to 8: the above 10 dates (1 January was then the Feast of the Circuмcision of Christ) minus the feasts the Body and Blood of Christ, and Saint Joseph. The present list was established in canon 1247 of the 1917 Code of Canon Law, now canon 1246 of the current Code of Canon Law.
Even before the time of Pius X, the bishops in many countries had obtained the Holy See's approval to diminish the number of non-Sunday holy days of obligation, making it less than 36. Today too, episcopal conferences have availed themselves of the authority granted them to reduce the number below the ten mentioned above.
https://en.wikipedia.org/wiki/Holy_day_of_obligation#:~:text=The%20following%20days%20must%20also,%C2%A72.