Are all animals phylum chordata

No! the Phylum chordata contains only vertebrates.

The phylum chordata is classified into three subphylums

a) Hemichordata

b) Urochordata

c) Cephalochordata

d) Vertebrata

a, b, c include animals which have invertebrate and vertebrate characters

The subphylum vertebrata includes the following classes

a) Pisces

b) Amphibians

c) Reptilia

d) Aves

e) Mammals