I tried to get a pattern by doing
$11^1 / 7 = 1 , r=4$
$11^2/7 = 17, r=2$
$11^3 / 7 = 190, r=1$
but the numbers keep getting larger and larger and I think this is not the way to go about this problem. Can someone please explain the correct way on how to deal with these problems?
$$11^3\equiv 1 \pmod{7}$$
$$11^{2020}\equiv 11^{3\cdot 673}\cdot 11 \equiv (1)^{673}\cdot {11}\equiv 4 \pmod 7$$