First install the mini Partition Wizard Manager.
Connect your sdcard into computer.
Backup all the files as in the process of making a partition you need to wipe all the data on the SD card.
Open mini Partition Wizard Manager tool , and open the Memory Card in it.
Right click on it, and select the “delete” option.
Right click on it again, and now select the option “Create New”, Create a “FAT32? partition. This will be the part of the memory card, where all your media files will be stored.
Then Select “Create as: Primary”
Then, create an ext2/ext3/ext4 partition ( if you are on stock ROM choose ext2). This is the place all your apps will be stored.
Then select “Create as:primary” (Make sure that it is both set as primary, because it will not be working if it is not set to primary).
And now click on the “Apply” button and wait for the changes to take place.
Now after made a partition on your sdcard, now to increase your internal memory. So that you can install as many apps as you want.
So follow these steps below.
Download and install the Link2SD app from play store
Open Link2SD. You will be prompted to choose between ext2,ext3,ext4 and FAT32. Now choose “ext2.
Done,now you can easily use your external storage as internal memory.See the below image:
Note: This app needs root access, so this trick would only work if you have rooted your phone.