What is poetic license?

It can include alteration of the conventions of grammar or language according to the poets will. He/She can change the spellings of different words so that it works well with their poem.For example : in the poetry The tale of custard the dragon, the lines : And a realio trulio little pet dragon , In this the poet have changed the spellings of real and true to realio and trulio so that it makes the poem rhyming and interesting to read. Hope you understand Regards