How can I create my personal brand?

A careear portfolio depends on the field you intend to get into and then every niche in that field will have different things employers will want to see.
Some careers may want certifications, artistic jobs will want a portfolio that demonstrates your creative skills in what ever the medium is.
Business or office jobs generally want a strong resume.

Determine your company, philosophy, what you are selling, target audience, value, and purpose. Then come up with your brand. Your brand is a great representation of what you are selling or the service you are offering. In addition your brand is your "social media" expert. It attracts attention by its name. Use names that reflects words used in search engines. Read: https://www.forbes.com/sites/shamahyder/2014/08/18/7-things-you-can-do-to-build-an-awesome-personal-brand/69de40f83c3a

For me, my personal brand has to do with how I conduct myself with co-workers and clients. Always showing respect and integrity, responding to emails within 24 hours, being collaborative, and producing high quality work are tenets of my personal brand.

While a personal brand is important, it can also detract from your attractiveness if you put your brand above the goals of your organization. Make sure the two are complimentary.

There are lots of great resources out there for you to do just that! I have included them below. Being in the leadership development space for 16+ years I can't emphasize enough the importance of this early on and throughout a career. I work with a lot of senior leaders who are considering their legacy and their brand has a lot to do with that.

Meanwhile - my advice and things I have done throughout my career.

1) Present yourself professionally while being yourself. Don't try and be someone different than who you truly are.

2) Consider how others perceive you - ask your friends, both close and acquaintances the first three words they would use to describe you - encourage honesty! Then ask yourself, is that who I want to be? If yes, great, continue to build on those. If not, consider how you need to change your behavior so others are saying the words you want them to say.

3) Be consistent. Your emotions, words and actions should align - including what you write and share on social media!

Depends if it's internally or externally, but generally your brand will only be credible and genuine via your credentials a d what these say about you rather than what you say about you. Use the "show, don't tell approach"