If you are near a larger parish, you can simply contact the secretary's office and ask if they have a program for adult entrants (called OCIA - Order of Christian Initiation of Adults).

For my German readers, here is a website where you can use your postal code to find a local contact:

https://www.katholisch-werden.de/taufe

For those in the USA, you can use this website to find the contact information of Catholic churches near you:

https://www.catholic.com/tract/catholic-answers-guide-for-getting-to-mass

The OCIA is explained well, here:

https://www.usccb.org/beliefs-and-teachings/who-we-teach/christian-initiation-of-adults