Salam,

Touching ones feet with the others feet is not neccessary.

The Hadeeth which refers to feet-to-feet is explained by the Muhadditheen to be an indication to standing close and straight in the Saff (line).
(Fathul Baari)

And if you are refering to your own feet being together in individual Salah, for males, there should be a gap between the feet. And for females, their ankles must be together.

And Allah knows best.