The House of Representatives impeachment managers walked across the Capitol in Washington, DC, to deliver the article of impeachment. The charges against Mr Trump were then read on the Senate floor.
Mr Trump left the White House last week before President Joe Biden was sworn in to become the 46th US President.
The 74-year-old refused to attend Mr Biden’s inauguration ceremony on Wednesday.
Mr Trump is the first President to snub a successor’s inauguration since 1869 and only the fourth President to have done so in US history.
Mr Trump also became the first US President to be impeached twice after he was charged by the House of Representatives with “incitement of insurrection” following the violent protests at Capitol Hill.
His Senate trial will decide whether he can ever run for US President again.
It will also be the fourth Senate impeachment trial of a President in US history.
The House’s lead impeachment manager, Representative Jamie Raskin of Maryland, read the article aloud on the Senate floor on Monday.
Mr Biden told CNN the impeachment trial of Mr Trump “has to happen” even if the chances of Republicans voting to convict the former president are small.
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According to CNN, multiple impeachment managers have said they do not think the trial will last as long as the 21 days of Mr Trump’s first impeachment in 2020.
Mr Trump was previously impeached in 2020 over claims he abused his presidential power by withholding aide from Ukraine in an attempt to pressure the country to investigate Mr Biden’s son.
For his second impeachment, the House speaker Nancy Pelosi tapped nine Democrats to be the House impeachment managers.
They will serve as prosecutors against Mr Trump in the trial.
In the impeachment article, the Democrats have accused Mr Trump of issuing false statements in the run up to President Biden’s certification.
They also claimed Mr Trump incited violence before the certification at the Capitol during a speech he made to his supporters.
The article read: “[Mr Trump] willfully made statements that, in context, encouraged — and foreseeably resulted in — lawless action at the Capitol, such as: ‘if you don’t fight like hell you’re not going to have a country anymore’.”
In a tweet on the day the Capitol was stormed, Mr Trump said the protesters were “great patriots” who had been “badly and unfairly treated for so long”.
As a result of the riots, the joint session of Congress certifying President-elect Biden’s victory was suspended and forced into recess.
Later that day when the Capitol was finally secured, Congress reconvened and continued to move forward with Mr Biden’s certification.