BBC political correspondent Ross Hawkins said Rudd remains under pressure to shorten a five-week wait before new universal credit claims are paid.
He added that Rudd may ask the Treasury for more money to implement further modifications, once the pilot scheme is completed.
Rudd told BBC Radio 4's Today programme: "I'm making a number of changes to our welfare system to make sure that it delivers on the intent which is to be a safety net and also to be a compassionate and fair system helping people into work."
Ahead of a speech on Friday announcing the changes, she also signalled a benefit freeze introduced in 2016 might not be renewed when it comes to an end next year.
"It was the right policy at the time... I look forward to it coming off," she told Sky News.
What is universal credit?
Universal credit is a benefit for working-age people, replacing six benefits and merging them into one payment:
It was designed to make claiming benefits simpler, and is being introduced in stages across the UK.
Confirming she would delay asking MPs to authorise the transfer of three million people from the old benefits system, she told Today: "We have listened to people. We know they want more individual assistance either with getting payments more regularly or having payments made direct to landlords."
"These elements, which could help universal credit work more helpfully for individuals receiving it, are what I'm going to be changing."
She also said she wanted to ensure that the main carer in a household would be the primary recipient of universal credit.
On the two-child limit, she will say in her speech later that it was "not right" for it to apply to those who had their children before the cap was announced.
"These parents made decisions about the size of the family when the previous system was the only system in place," she will say.
The "child element" of universal credit varies, but is worth at least £231.67 a child per month.
Rudd, who became work and pensions secretary in November, accepted there were problems with universal credit, and promised to "learn from errors" and "adjust" the system after taking expert guidance.
Her predecessor Esther McVey had already announced changes to ensure claimants were given more time to switch to the benefit and would not have to wait so long for their money.