To work, a drawing tablet pen requires a little power. Either a pen will get power from the tablet wirelessly (Passive EMR) or the pen will use a battery (Active EMR). For a many years now, tablets exclusively use Passive EMR pens.
Passive EMR refers to the EMR technology where tablets wirelessly power the pen. All modern drawing tablets use Passive EMR. Their pens get their power just be being close to the tablet (about 10mm). The pens don't have a battery that needs to be recharged or replaced.
Wacom has been using Passive EMR for many decades. For non-Wacom table brands, they made the transition to Passive EMR with the last 10 years.
In contrast, Active EMR is when the pen is powered by an internal battery. The battery is either replaceable or rechargeable. If it is rechargeable, then the tablet will come with a special cable that plugs into the pen and then usually to a USB port on your computer for charging.
Passive EMR tablets can only be used with Passive EMR pens
Active EMR tablets can only be used with Active EMR pens
If you have have an older Active EMR pen, you cannot replace it with a Passive EMR pen.