Apply Visa website & IHS fee

After RCOS granted, I believe need a certificate number from my company and go to website apply visa? Am I correct? Can I do it by myself?

Which website should I use? Any advice?
1) https://www.visa4uk.fco.gov.uk/ >> I used this to apply Tier 5 visa,2 years ago.
2) https://mycart.vfsglobal.co.uk/ >>I saw this website have Priority Visa Service, but it showed before you can purchase premium services you should have completed an online application form and have a valid application number from https://visas-immigration.service.gov.u ... type/tier2 ?
3) https://visas-immigration.service.gov.u ... type/tier2 , if I want apply premium services can I use this website?

For my understanding, I need to apply from my home country, I need to give all my document in home country visa centre? I register at website, fill up all the information they require. Book an appointment,Pay visa fees, Visit the visa application centre to handover all my documents.

However my lawyer asked for Professional Fees
As previously discussed, we charge you a fixed legal Admin fee of £600 prepare and submit your Tier 2
(General) application for entry clearance. The fee includes making representations to the Home Office,
informing you of any developments as and when they arise and submission of all necessary documentation.
>>>However all the documents are with me apart from certificate number. I do not understand how can they arise and submission of all necessary documentation.

Is this necessary to pay this Professional Fees? As I applied tier 5 visa by myself 2 years ago, I think the difference is just the certificate number from my company, not too much differences. I think I can apply this by my own.

Also I saw the article about the IHS Fee Increase Announcement Approved on Nov 22, 2018, will it effect application on December 2018? or even November 2018?As I am still waiting my company provide certificate number.

Thank you.

Any advice for applying visa website?

And Can I request for inclusion in Tier 2 Priority Service even I am not in UK? Or it is only for UK applications?

I can answer part of your questions.

1. Correct. You can use visa4uk to apply for Visa outside UK.

2. Priority service. You can use priority service but sometimes they don't guarantee priority promises. Depending on how busy they are.

3. Not sure about the third one.

Using a solicitor or not depends on how confident you are with the application.

Can your solicitor represent you overseas as you will be away from UK?

Where will you be applying from?