i do not have option in settings to turn on hot spot

You will only see Cellular hotspot settings if your iPad’s Cellular tariff/subscription permits WiFi tethering.

Some carriers won’t permit tethering at all, while others may charge an additional fee for this feature - and/or may “cap” the amount of Cellular data that can be shared via the hotspot.

For your iPad to share its Cellular connection via tethering (hotspot), your physical DataSIM (or eSIM plan if used) must be explicitly provisioned to use this feature by the Cellular Carrier.

How to set up a Personal Hotspot on your iPhone or iPad - Apple Support

Are you suggesting that you are attempting to use your iPhone SIM with your iPad?

The majority of mobile phone SIMs are not correctly provisioned for use with tablet computers. If they work at all, they may not provide access to the full range of cellular services. This is not a limitation of the iPad, but of the Cellular network provider’s configuration of the SIM.

If using a physical SIM with iPad, you will require a DataSIM explicitly provisioned for iPad or mobile broadband (a.k.a. MiFi). As already outlined, the cellular plan associated with the DataSIM must explicitly enable tethering for the iPad.

Be aware that an iPad, whether a Cellular model or not, is not capable of directly accessing Cellular Voice or SMS/MMS Messaging features. An iPad with either WiFi or Cellular connectivity alone can only access IP-data services. If you have added a DataSIM and Cellular plan to a WiFi+Cellular model of iPad, the number associated with the SIM card is only used to identify your account for billing purposes. This number is not used for making calls or sending messages.