You can define the geography for the territory from the CRM backend. To define the geography of the territory, navigate to the Advanced Settings → Settings → Business Management. 
You will see the Sales Territories option to manage the territories from the CRM backend. You can also define the geography of the territory as well.
By clicking on the “Sales Territories”, you will be redirected to the list of the sales territories page. You can create a new territory and define its geography.
By clicking on the + New option from the header menu of Dynamics 365, a new web browser will open to configure the new territory by defining the geography. 
Once the general details are added, you need to save the territory and the territory is created. After that, you can define geography. If you want to add the territory under another territory, you can select the main (parent) territory in the “Parent” option. 
Now, by clicking on the Define Geography tab, you can define the geographical area of the territory on the MappyField 365 only.
Click on the “Territory Management” and then plot the territory by using search options. 
Now, the territory is plotted as per the search options. 
Once the territory is plotted, you need to select the territory using the selection tool (hand icon). 
After selecting the area using the selection tool, you need to right-click on the selected territory (area) to create new geography. 
You can see the added geography in the list. You can add multiple geographies (areas) for the same territory by searching options. 
You need to click on the Save option to save the territory with the geography. Once you add the geography, you or CRM users can plot it as a Territory in the MappyField 365 map.