Tiss the place all your treasure are kept, look after it.
Storage has become ridiculously cheap these days. And there are multiple choices too. You could opt for the traditional external hard drive option. You could also opt for cloud storage. The first thing that you should keep in mind when deciding on your preferred storage option is that it must be able to survive multiple failures. Redundancy is the key word in storage. Redundancy denotes you back up your images and RAW files on multiple locations and at multiple locations to avoid the failure of any one location to jeopardize your entire repository of files and folders.
The preferred choice these days seems to be the external hard drive option. External hard drives are very cheap and they come in various storage capacities. A standard 4 TB of storage is a good place to start with. Buy at least 2 of these to form what would be a RAID 1 configuration where each drive is a mirror image of the other without any stripping and without any parity.
For larger requirements where you regularly deal with huge volumes of data (professional photographer) you should go for a third drive that you keep at a different location and is used as a permanent archive in case the other two fail.
For large chunks of data you will need to keep multiple hard drives that can be bifurcated based on month or quarter according to your volume of work.
Cloud storage is yet another option that you can look into. Cloud storage entails using logical pools of servers which are distributed over a large number of physical servers. Often these servers are distributed over a number of locations (not necessarily though). The advantage in this type of storage is the scalability factor. You can add storage on demand and have a global access of your data on the fly.