If you have duplicate leads in your pipeline or if you want to merge two leads, you can merge leads by using Merge Leads option. You can Merge Leads via Lead View and via List View.
1. Merge Leads from Lead View
To merge leads, click on the lead in the pipeline.
Once you're inside the lead, click on the Merge button in the top menu beside the lead name (highlighted below).
After clicking the button, a popup window will open where you need to enter the lead you want to merge this lead with. Once you start typing, the lead name will show up in the drop-down menu and then you can select it.
After you select the lead, a message will show up in the next screen informing that all the data you have in this lead will be transferred to the other lead and this action cannot be undone. There is a red button below it which says "Yes I want to merge the leads". Click on it and your lead will get merged with the other lead.
2. Merge Leads from List View
You can also merge leads from the List View. To move to List View format, click on the View option from the Pipeline menu.
The List View looks like this:-
Now select your leads by ticking on the checkboxes, and you will see an Actions button appear in the top bar. Click on it and then click on Merge in the drop-down menu. Refer to the highlighted in the image below.
A popup window will open where you will be able to see the leads selected to merge. Now under it, you must type in a name for a lead where the data of all the above leads will be merged. Then select the stage you want add this lead to and assign this lead to a user or keep it unassigned. Once you're done with the steps, click on Merge Leads. Your leads will be merged into that lead. Refer to the highlighted in the image below.