Delete or format partition during clean install windows

Hey guys i just join this forum and today i've plan to clean install my PC well i kinda noob with this one and i like to ask some question. Once you get to the Custom (Advanced) tab of Windows 10 clean install there are options to delete the partition, format, etc. Which one should i choose format or delete ? Or maybe i can do both like first format then delete ? Whats your guys recommendation and what's the different ?
Thanks in advance. Excuse my english.

So i just have to delete it without formating to make it unallocated right ?
I kinda confuse because in some tutorial they do both or either.

The good thing about deleting the partitions is that Windows 10 will create fresh, new System and Recovery partitions. They can get corrupted too, so if you are going to start with a fresh Windows 10 partition, might as well start with all fresh partitions.

I had 100mb system partition like your drive 0 partition 2 but after booting windows when i check the partitions from disk manager
It shows 100 mb is 100% free.
I doubt if something got wrong
So can you check if its 100% free after booting and tell me

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Avocado said:

Step 1:

If the entire hard drive not show as unallocated space, then delete all partitions on the hard drive until it's unallocated (see screenshot below). Select a partition and click on the "Delete" option for each partition.



Step 2:

- Option 1:

Click on the "Next" button. The installation of Windows 10 will begin. All the required partitions are created automatically during the install.

- Option 2:

Select the "New" and "Apply" buttons.







Click on the "Next" button. The installation of Windows 10 will begin.

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For more info about UEFI mode and Legacy BIOS mode, look at post #5 in this thread: Cant install Windows 10 because of GPT partition error message

I had 100mb system partition like your drive 0 partition 2 but after booting windows when i check the partitions from disk manager
It shows 100 mb is 100% free.
I doubt if something got wrong
So can you check if its 100% free after booting and tell me

The number and type of partitions may vary from Legacy-MBR to UEFI-GPT and even on different Windows versions.
Just remember:
- To install as Legacy-MBR you must boot the installation drive as Legacy.
- To install as UEFI-GPT you must boot the installation drive as UEFI.

As NavyLCDR suggested, delete all partitions and proceed. The necessary partitions (type & size) will be created.