kitchen appliance from North America to Oman?

High power units, that's anything with a motor or heater, will require big adaptors if they operate at 110v and you intend to use them on a 240v system.
Such things are big and ugly so, apart from the cost of transporting your stuff, you'll have to find a place that sells the transformers and stand the cost of buying them.

People will tell you they're available all over, but the things they talk about are low power units good for a mobile phone charger.

That changes if the equipment is multi voltage, you can check that on the labels.

thanks for your response. do you know where can i find those transformers?

Why not search online? Big online selling websites such as Amazon and eBay should have what you want. The question is you need to spend some time to pick up the suitable one. I also placed an order for [link moderated] last month from Amazon. Not regretful yet - I mean, it is working good.