Protein-histidine N-methyltransferase that mediates methylation of target protein on His residues. L-histidyl-[protein] + S-adenosyl-L-methionine = H(+) + N(tele)-methyl-L-histidyl-[protein] + S-adenosyl-L-homocysteine Belongs to the methyltransferase superfamily. METTL18 family.