Date of Application

Dear All
Apologies if you have already answered these questions. However I could not find the answers what I want.
I am applying for naturalisation in a couple of weeks.

My questions regarding previous UK immigration applications

1. Is my visitor visa (research visitor) considered as an immigration application?

2. Is my Tier-2 (Gen) visa application considered as an immigration application?

3. I do not have the reference numbers for my applications and I do not remember the dates of application, can these things be replaced by visa numbers and dates of issue?

4. Is my Tier-2 (General) visa extension application considered as a separate application?

I really appreciate your time in replying for these questions.
Many thanks
S

1. All and each application made.

2. All and each application made.

3. The question does say 'IF KNOWN'!!

4. Yes, all and each application made.

Many thanks and I really appreciate your quick reply.

Dear All
I hope you are all safe and healthy.
I have a quick question. For the naturalisation application, what is the correct date of application?

Is it the date at which you submit the application online and pay the money?
or
Is it the date at which you give your biometrics?

Many thanks

It's

the date at which you submit the application online and pay the money

.