Cats with hyperthyroidism can be treated in 4 ways: do nothing, surgically remove the thyroid, radioactive iodine and anti-thyroid tablets. Most people opt for tablets as they are cheaper than referral for surgery or for the radioactive treatment.
Unfortunately hyperthyroid cats are known for being grumpy, which doesn't make giving them tablets any easier! If they can be ground up, you could try mixing the ground tablet into butter and smearing it on your cats paw - as she licks it off she ingests the tablet. Hiding the tablets in food works if she doesn't poke around in it too much. You can also buy pill poppers from some places - you put the tablet at the end and it allows you to place the tablet at the back of the cats throat without you getting your fingers knawed ff in the process!