How to get warranty for your product if you buy a gadget online?

A lot of products are sold online especially the gadgets like ipad, iphone, cameras, laptops, etc.
but do you have warranty for those products? What if something happens with your gadget after 1 month from the date of purchase?

Do they offer warranty for their products online? Most of them are not from the company itself, they are just selling brand new products online.

I'm thinking it depends what it is. On some websites like take lenovo for example you can buy extended warrenty on their website.

Warranties are nearly always covered by the manufacturer, not the seller of the item. There are a few exceptions where you return the item to the place you purchased it, but not too often. You just contact the manufacturer and get instructions from them for returning a defective product for repair or replacement. They usually have an 800 number for this service. The one place you must be very wary of buying products that may not include a manufacturers warranty is eBay! Some eBay sellers buy huge quantities of manufacturers overruns, so the product may have been manufactured a couple of years ago and there are no replacement parts for repair available. The unscrupulous sellers even advertise a "Full manufacturers Warranty" in their add, and then you find out from the manufacturer when there's a problem that you now own a piece of junk that will cost 75% of the price of new model to repair IF it can be repaired. If the item I want is available locally, that's where I buy it! It may be worth an extra $20 to have some peace of mind!