Work Phone

You can sure, but there will be side effects to that.

If you use the same Apple ID for iCloud and Messages and Facetime on both devices, then calls, and messages and icloud data will be synced across both devices, so you will get calls and messages from one phone on the other phone and vice versa. You might want to verify that your work allows this.

If you just want to share purchases, you can use the same Apple ID for iTunes and App Stores, and have a different Apple ID for iCloud, Messages and Facetime.

See here for other things that will be linked: Use Continuity to connect your Mac, iPhone, iPad, iPod touch, and Apple Watch - Apple Support

kaine187 wrote:

...

For example a client has my iPhone se number and rings me - if I use the same Apple ID will it ring on both phones?

Yes, if they are connected to the same Wifi network when the call comes in.

Make and receive calls on your Mac, iPad, or iPod touch - Apple Support

Check with your work to see if they have a device management program on it. If not, see if it would be possible to use your ID on it. If you do, make sure you remove it if you ever leave the job.

kaine187 wrote:

But if they are not on wifi and just 4G then it would only ring on the phone which had the SIM card for the number rung.

Correct.