How to get siri on ipad2 ios 8.1.2

because its not on the latest iOS i think the iPad 2 goes up to iOS 8 the apps are on iOS 11had the same problem i had to buy a up to date ipad

To use Siri, simply hold your thumb or finger down on the power button. You will hear a double tone when it is open. For Siri settings, go to Settings, General, then check for Siri either in the left hand menu (IOS 10) or on the right side menu.

Siri troubleshooting: Siri's not working at all on my device. Which iPhone/iPad models can run Siri? If Siri isn't working for you, the first thing to check is your model of iPad or iPhone - older devices can't run Siri, even if they update to a newer version of iOS. Siri is available on the iPhone 4s and later, on the iPad 3, iPad 4, and all iPad Pro, iPadAir and iPad mini models, and on the 5th- and 6th-gen iPod touch models. Plus the Apple Watch and 4th-gen Apple TV, of course Siri troubleshooting: How to turn Siri on If it's not working at all, Siri might be switched off. Go to Settings > General > Siri and make sure the top slider (next to Siri) is on, and green.

I don't think Siri is on the iPad 2.

you cannot delete them:
there are some core apps belonging to the iOS system and cannot be deleted like 'clock', 'calendar', 'contacts', 'facebook' etc.
- however you may create a folder (unwanted apps) and put them there, then they are at least out of sight and use less desktop space.....
1) Airdrop
2) Apple Store
3) calendar
4) camera
5) clock
6) contacts
7) facebook
8) game center
9) iBooks
10) iTunes
11) mail
12) maps
13) messages
14) music
15) newsstand
16) notes
17) photo booth
18) photos
19) reminders
20) safari
21) settings
22) siri
23) tips
24) touch ID
25) videos
How to create Nested Folders in iOS 7 Video

there are some core apps belonging to the iOS system and cannot be deleted like 'clock', 'calendar', 'contacts', 'facebook' etc.
--------------------------------------------------
core apps:
1) Airdrop
2) Apple Store
3) calendar
4) camera
5) clock
6) contacts
7) facebook
8) game center
9) iBooks
10) iTunes
11) mail
12) maps
13) messages
14) music
15) newsstand
16) notes
17) photo booth
18) photos
19) reminders
20) safari
21) settings
22) siri
23) tips
24) touch ID
25) videos

Check out this Apple article. Update the iOS software on your iPhone iPad and iPod touch
It explains the different ways you can update your iOS.

core apps of iOS which cannot be deleted!
1) Airdrop
2) Apple Store
3) calendar
4) camera
5) clock
6) contacts
7) facebook
8) game center
9) iBooks
10) iTunes
11) mail
12) maps
13) messages
14) music
15) newsstand
16) notes
17) photo booth
18) photos
19) reminders
20) safari
21) settings
22) siri
23) tips
24) touch ID
25) videos
- here are 2 different ways to delete an App:
1) t's easy to delete apps from the iPhone or iPad. Simply tap and hold on any icon for about 2 seconds - see them to start to wiggle and tap the X button in the left corner. that's it.
2) For devices running iOS 5 and later, there is also another way to do this is hidden in the Settings app, in the General tab, under: usage.

How to do I update to iOS 5?
There are two ways to upgrade the iOS version of your iPad
- via connecting the device to iTunes on a computer
- or directly from within the device, but only since iOS 5, it is possible to upgrade the iOS version without the need to connect the iOS device to a computer (over-the-air update)
just go to: settings - general - software update

probably it helps to update your system to the newest
iOS 8.1.2
- there might be a compability conflict between the app and iOS version....

How to Install iOS 8 1 2 On iPhone iPad and iPod Touch