You may keep a safe at home to store and protect important documents and items; however, you may not need to use the safe all that regularly. Once you've stored stuff in there, you may not need to open the safe again for a long while if you don't need to get at or add to the contents. If you're not regularly opening your safe, however, then you may find that you've forgotten the combination when you try to open it. Even if you've written the code down somewhere, you may have stored it in such as safe place that you've forgotten where it is. How can you get into your safe now?
Consult the Manual
The manual that came with your safe probably has a section on what to do if you've lost your combination. For example, some safes have override factory codes that you can use to open safes at any time—if your safe has a factory code, then the manual should tell you where to find it. If you didn't keep the manual or can't find it, then you may need to contact the manufacturer for help.
Contact the Manufacturer
It's quite common for people to forget safe combinations, so your safe's manufacturer should be able to help you regain access. To start with, search for the manufacturer online and see if there is any information on lost combinations on the company's website. This is often contained in FAQ pages.
If you can't find a fix this way, then call the company. They will be able to tell you what you need to do to get a replacement combination. Bear in mind that this may take some work and some time—you may have to provide a sales receipt, proof of ID and data from the safe such as its serial numbers.
In some cases, this may be trickier than it seems, say if you've not kept your receipt or have peeled the stickers that held serial numbers off the safe. Don't assume that you're stuck if you can't provide the information that the safe manufacturer needs, and don't worry if you need to get in the safe urgently and can't wait to get a new code. Call local locksmiths and ask if they can help. Locksmiths can open safes when the combination is lost and can then reset the code to give you a new combination for the future. A residential locksmith could visit your home and sort out your problem really quickly—just remember not to lose the code again when you get a new one!