How is the action of exonuclease different from endonuclease?

Endonucleases are nuclease enzymes that catalyze the hydrolysis of nucleic acids, but they only break internal phosphodiester bonds; they do not recognize terminal nucleotides as substrates. The cleavage of terminal phosphodiester bonds is carried out by exonucleases.

Hi Student
Exonuclease are enzymes that cleave the nucleotides at the end of the DNA molecule.
The cleavage by exonuclease results in the formation of nucleotides or nucleosides.
For example- BAL31
Endonuclease are enzymes that cleave the bonds of the DNA from within the molecule(middle part) at specific site.
The cleavage by endonuclease results in the formation of oligonucleotides(Four nucleotide residues).Fopr example- S1 nuclease, Dnases, Restriction endonucleases.