Martha is from the Aramaic Marta (lady, mistress of the house). In the Gospel of Luke, Martha of Bethany was the sister of Lazarus and Mary who busied herself with hospitality while her sister sat at Jesus's feet — Jesus's gentle admonition ("Martha, Martha, you are anxious and troubled about many things") gave the English language its archetype of the busy hostess.
Martha does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Martha reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.