June 21 (Reuters) - Mortgage software maker Blend Labs Inc on Monday made public its paperwork for a U.S. initial public offering and revealed a 90% jump in 2020 revenue, helped by the pandemic-led shift to digital banking services.

The San Francisco-based company had confidentially filed for a listing in April and was valued at $3.3 billion after a funding round in January, according to media reports.

Blend Labs, a digital platform for lenders to offer mortgage and consumer loans, on average processes more than $5 billion in transactions per day, its website showed. It counts Wells Fargo & Co and Lennar Mortgage as some of its customers.

The company's filing with the U.S. Securities and Exchange Commission used a placeholder figure of $100 million for the offering. It gave no other indication of the size of the offering or potential valuation.

Blend Labs said its 2020 revenue rose to $96 million from $50.7 million a year earlier as homebound customers increasingly turned to online banking services during the COVID-19 pandemic.

Fintechs are fast becoming a force to reckon with, even for longstanding traditional financial institutions. Brazilian digital bank Nubank is also weighing a U.S. IPO that could value it over $40 billion, Reuters reported on Monday.

Blend's IPO is being underwritten by a syndicate of banks led by Goldman Sachs & Co, Allen & Company and Wells Fargo Securities. The company's shares will be listed on the NYSE under the symbol "BLND". (Reporting by Niket Nishant in Bengaluru; Editing by Ramakrishnan M.)