How can i link the device IP in the map?

Unfortunately, there's no such item available PRTG and you have to build it yourself. Here's an object that displays comments of an object:
Since this is not generated automatically, you'll neeed a script that iterates through the devices and puts the IP address in the comment of it:

[xml]$Devices = (New-Object System.Net.WebClient).DownloadString(http://<your-prtg-server>/api/table.xml?content=devices&output=xml&columns=objid,host&username=<prtg-user>&passhash=<passhash>)
foreach($Device in $Devices.Item) 
{ 
    $ips = [System.Net.Dns]::GetHostAddresses("$Device.Host")
    Invoke-WebRequest "http://<ihr-prtg-server>/api/setobjectproperty.htm?id=$Device.Objid&name=Comments$value=$ips[1].IPAddressToString&username=<prtg-user>&passhash=<passhash>"
} 

This is just a proof of concept and probably needs some tweaking. What it basically has to do:

1. Retrieve list of all devices via PRTGs API.
2. Parse the XML into a PowerShell object
3. Resolve the host for each object
4. Put the IPv4 string into the comment device

Create a new map object (e.g. C:\Program Files (x86)\PRTG Network Monitor\webroot\mapobjects\device_comment.htm) with the following code:

<!-- Devices: Device comment -->
<div class="map_object" id="<@itemid>" objectid="<@objectid>" subid="<@subid>" style="<#mapobject type="coordinates" subid="<@subid>" mode="<@editmode>">">
  <#mapobject type="objectgrip" mode="<@editmode>">
  <#mapobject type="htmlbefore" subid="<@subid>">
  <#checkobjecttype objecttype="device" nicemessage="true" id="<@objectid>">
  <#objectstatus name="comments"  id="<@objectid>">
  <#mapobject type="htmlafter" subid="<@subid>">
</div>

This will show the device comment as simple text on the map as shown above. Add <b>IP: </b> to the HTML Before field of the object to prepend some text to it.

Where does this go?

[xml]$Devices = (New-Object System.Net.WebClient).DownloadString(http://<ihr-prtg-server>/api/table.xml?content=devices&output=xml&columns=objid,host&username=<prtg-user>&passhash=<passhash>) foreach($Device in $Devices.Item) { $ips = [System.Net.Dns]::GetHostAddresses("$Device.Host") Invoke-WebRequest "http://<ihr-prtg-server>/api/setobjectproperty.htm?id=$Device.Objid&name=Comments$value=$ips[1].IPAddressToString&username=<prtg-user>&passhash=<passhash>" }

This script needs to be executed with a scheduled task like every 30 minutes, depending on how up to date you want the IPs to be :)