In Salesforce we can convert the leads based on Lead’s Field Value. To set up this we can use the below validation rules.
In this example we used the custom field as “Lead Qualified” is equal to “Yes”
Step 1 : Go to Setup
Step 2 : Click Object Manager
Step 3 : Select Lead Object
Step 4 : Create a Validation rule
Error Condition Formula :
AND( IsConverted, NOT( TEXT( PRIORVALUE(Lead_Qualified__c) ) = “Yes”) )
Step 5 : Click save
If the Lead Qualified field value is not equal to Yes. Then the below error will occur when doing convert action.
If the Lead Qualified field value is “Yes” then it will be converted successfully.