SEP Contributions from Partnership

Can Partnerships contribute to SEP IRAs? I have a K-1 the shows $300K distributions from the partnership and W2 that has $65,052 in boxes 1,3 & 5. Do each of the 2 partners in the partnerships need to contribute to a SEP IRA? How is the maximum SEP calculated? I know it’s from earned income but is there a specific definition of earned income? Also, what is the deadline?

Thanks!