The meaning is the same, but the verb "seek" is quite formal and old-fashioned.
There are certain written contexts where "seek" might be appropriate, but you will probably never need to use it. My advice to you would be to always use "look for" in everyday contexts - for example, here on italki, you'd say that you're looking for a language partner, or you would go into a shop and tell the shop assistant what you are looking for.
Don't worry about trying to use "seek" - we don't often write it and we very rarely use it in conversation.