Right-click the partition you want to keep and select the Merge or Merge Partition option.
If you have an empty partition, is the fastest way to merge. If you have data on both and don't want to move it manually, a third-party tool is your best bet. how to merge two partitions
Often, a small "Recovery Partition" sits between your C: drive and your data drive. This acts as a wall, preventing you from extending the C: drive. You’ll need a third-party tool to move or delete that recovery block safely. Summary Right-click the partition you want to keep and