Proxy Voting

The House has always banned proxy voting on the floor.  CRS explains proxy voting in committee:

Before 1995, members could leave their proxies with one of their committee
colleagues to cast for them. This often enabled a committee chair, if he or she held enough proxies, to win a roll call vote even when the chair’s position was opposed by a majority of the members who actually were present.

Proxy voting was prohibited in 1995. The result has been to put more of a premium on
maximizing attendance, especially when the majority party holds only a few more committee seats than the minority. In those circumstances, the absence of only one or two majority party members can enable the minority party to prevail on a party-line vote if all the minority party members are present. It is very important, therefore, for as many members as possible to attend markups and for the committee staff of each party to know how to contact their absent members as soon as a roll call vote begins (if not before). Committee staffs may devise systems to keep track of where their party’s members are and may rely on members’ legislative assistants to ensure that those members are present when they are needed to make a quorum or to cast their votes.

The Senate allows proxy voting in committee but not on the floor.

Katherine Tully-McManus at Roll Call:

The House is expected to vote as soon as Thursday on a major, but temporary, change to the chamber's voting rules to allow for proxy voting as travel and large gatherings continue to pose public health risks during the coronavirus pandemic.

Lawmakers are expected to have to return to Washington this week to vote on an update to coronavirus pandemic aid for small businesses, and House leaders plan to use the session to also approve an emergency proxy-voting procedure in response to the health crisis. The change would allow an absent lawmaker to designate a colleague to vote on House floor matters on their behalf.

House Majority Leader Steny H. Hoyer, D-Md., announced late Monday night that if the Senate passes the small-business aid in their Tuesday pro forma session, the House could meet as soon as Thursday at 10 a.m., when a proxy-voting resolution may be brought for a vote.

House Rules Chairman Jim McGovern, D-Mass., floated the proxy-voting and rule change proposal last week, in response to calls from within his caucus for leadership to establish a system for remote voting to allow the House to continue pressing legislative business during the COVID-19 crisis.

Many lawmakers thought that technology could be the solution to allow remote voting, but concerns about cybersecurity, outside intrusion and lack of time for testing led McGovern and House leadership to move forward with a low-tech proxy solution.

House members who remained in their district would send a letter, electronically, to the clerk to authorize another member to vote on their behalf and would provide exact instruction on how to vote. The authorization could be updated as procedural or other unexpected votes arise during the session.

Members able and willing to vote in person on their own behalf could still do so. Members physically present would be eligible to cast votes on behalf of their colleagues.