Can you learn to sing in tune?
Most people can. True tone deafness (congenital amusia) affects about 1.5% of people (Peretz & Vuvan (2017), European Journal of Human Genetics). Most people who think they can't sing in tune can hear the difference; their voice just hasn't learned to land the notes yet.
What helps is feedback on every note: sing, see exactly how far off you were, adjust, repeat. That loop is what a teacher gives you once a week, and what Singsteady measures every day.
More questions: Is there an app that checks if I'm singing in tune? · How accurate is an online pitch or vocal range test? · What is a cent in singing? · How do I find my vocal range? · How do I sing high notes without straining?