Yes, first you need to resize the partition to accommodate the new OS. Usually 40-60 GB is good enough for minimal linux installation if you didn't do any gaming or other massive applications. The resizing can be done in windows using disk management utility baked into windows, or some other partition manager (easeus, magic tools, etc). After that, linux can be safely installed in the free space as a single partition.
Now, sometimes the bootloader is fucked, but it is quite easy to fix. In fact, if you use grub, it usually runs os-probe for you to check for any other OS. So sometimes, fixing it is as simple as rerunning grubmkconfig. But there are other times where it is not as simple. It will vary depending on what happened and too long to list here. Arch Wiki usually covers a lot of the topic so you could try searching there, especially on the topic of boot sequence.
Lastly, if you need to move the partition, the data already inside will need to be moved too. This can take time depending on the size. But it is doable and safe.
If, later down the road you want to remove either OS, you can simply remove the partition after moving the data first. Linux can mount ntfs natively so no problem there. On windows, there is a program called ext4 explorer or something along the line to browse and copy from linux filesystem (which is usually ext4). Don't forget to remove the boot information too after you're done removing the partition.
Now there is also the other suggestion to use a live environment but I didn't suggest it since the experience can be lacking and more hassle in and of itself.