Web Development

That depends on your requirements for the site and your own competencies.

Either option is a yes. We can't know your goals and skills so the answer is yes.

I know companies the do it themselves and some that hire it out.

An individual web designer or developer is able to set his or her own rates. Therefore, the cost of the overall project can be cheaper than options with a web agency. If your business is just starting out and needs a simple web presence, a freelancer or very small agency can be a good choice.
Advantages of Working With a Freelancer
There are several advantages to hiring a freelancer to complete your project.

Cost
Cost is one of the biggest reasons that a business may select a freelancer over an agency to create its website. An individual web designer or developer is able to set his or her own rates.

Therefore, the cost of the overall project can be cheaper than options with a web agency. If your business is just starting out and needs a simple web presence, a freelancer or very small agency can be a good choice.

Involvement
Along with setting their own rates, freelancers can set their schedule. This can positively impact the timeline of the project.

When working with individuals, they may be able to devote all their time to your project to get the work done faster, whereas an agency will be managing multiple projects with different timelines.

Disadvantages of Working With a Freelancer
Although a freelancer can be less expensive and more involved than a web design agency, there are also potential issues with hiring one.

Accountability
When hiring a freelancer for any type of project, accountability is always a concern. While some freelancers come highly recommended, it can be more difficult to assess the reviews and experience of a freelancer compared to an agency.

Limited Skillset
One of the biggest disadvantages of working with a freelancer is that you are limited to the skills and resources of that person.

Designing and building a website is similar to building a house in that it requires a lot of different skill sets. You wouldn’t expect the architect to also do the plumbing nor the construction crew to help with the interior design of the house.

Advantages of Working with an Agency
A web design agency can be the best choice for your company's project because of the different advantages it offers over a freelancer.

Diverse Experience
The major advantage of working with a web agency is that you’ll have a team dedicated to the web project, including a web strategist, a web designer, a project manager and a web developer or development team.

Credibility & Support
Another advantage of working with a web agency is that an agency typic

Here's what an agency can do for you:
Enable you and your team to have more time to create, sell, innovate and move your business forward.

Align your ideal buyer with seamless conversion optimising experiences and brilliantly innovative UX.

Transform your current site. Returning customers benefit from the ease of use, new customers are impressed with your style and substance.

To build a single website you have many options such as
1. Take help from a freelancer
2. By own

By own:-
I think you can also make a website by own if you have some programming knowledge like
HTML and CSS which is used to make an attractive webpage
.JavaScript:- which is used to provide life to the webpage.
and most important part is PHP which is used to handle the website's database.

But if you don't have any programming language you can help WordPress to make websites most people prefer.
Now the third option is you can take help of agencies which will give a website or websites with full satisfaction and according to your demand.
thanks:)