A long email containing text, some attached images, and a couple of links to YouTube videos.
Pros:
+ easy to create, edit, and customize
+ no software or platform needed
Cons:
- you can't update anything. So if you have a new project in the portfolio or your prices have changed, this person will never know it if you have no website.
- it looks a bit primitive
- no video in text, only links
- no more than 25 MB of content - not enough for your portfolio
- no interactive elements, such as 360-degree tours
- no analytics available, the only option is email tracking--you will know when your email was opened. In most cases, this feature will cost you about $5 a month.

A colored and stylized email made from templates on Wix, Mailchimp or another platform.
Pros:
+ looks nicer than a basic email
Cons:
- it's still just an email, so all the cons of a regular email are applicable to it
- you'll need to learn a new (but very convenient) software
- it's a paid service, $5 - $10 / month.

Pros:
+ may look nice if you hire a graphic designer
+ may contain a lot of text with a good structure
Cons:
- you'll need to invest a lot of time, energy, and sometimes money to make it look professional
- can't be updated after sending
- in many cases, it will be difficult to add video
- no interactive elements, such as 360-degree tours
- no analytics.

Pros:
+ most of us already own one
+ Instagram looks like it was created for use as an online portfolio
+ the number of followers, likes, and comments you get may help you gain the trust of potential clients
+ your clients may want to follow you so that can read your new posts
Cons:
- it is difficult to structure information so that your client will easily find what he wants to know
- it takes time to create a creditable account

Pros:
+ clients can find you when they are searching for a professional architect or designer
+ great structure of information
+ testimonials and ratings will add creditability
+ you can add as many projects with photos as you want
+ easy to update
Cons:
- you might not want to give a link on your Houzz page for potential customers to inquire about your services, because a lot of your competitors are also on Houzz
- you can't create a unique look for your account
- you can't use 360-degree tours or any other interactive elements.

Pros:
+ thanks to modern platforms like Wix, Foursquare, Jimdo, Tilda, etc., creation of a personal website has become easy
+ galleries of images and videos
+ 360-degree tours and any other features that can be used in a web browser
+ you can structure content the way you want
+ you can choose from many beautiful templates or create your own design
+ easy to update
+ can be integrated with your Instagram feed
+ you can share information about your services simply by sending only the address of your website
+ you can print your domain name on your business card
+ you can get a custom email address (like anna@3danna.com)

Cons:
- you have to learn how to edit it
- it's a paid service ($5 - $10 / month)
- in most cases, you might want to buy a domain name ($15-$25 / year).