There has been much discussion about whether votes in this next election will be counted securely.
Every state has rules about what poll observers can do at the polls and how votes can be challenged. Here are the rules for your state:
Iowa Poll watchers may be appointed by the following: political party executive or central committees; non-party political organizations (NPPOs); candidates who are “Nominated by Petition,” and groups opposing or supporting public measures on the ballot. Poll watchers may also be called challenging committees or observers. Poll watchers acting as challengers must be registered voters in the county where the challenge occurs. While the polls are open on election day, there is a limit to the number of poll watchers that can be in a polling place: 3 appointed by each political party that has a candidate on the ballot; 1 appointed by each NPPO that has a candidate on the ballot; 1 appointed by each candidate nominated by petition, and 3 for public measures on the ballot (except for primary and general elections). (Iowa Poll Watchers Guide).
The following persons shall be permitted to be present at and in the immediate vicinity of the polling places, provided they do not solicit votes: a person who is by law authorized to perform or is charged with the performance of official duties at the election; any number of persons, not exceeding three at a time from each political party having candidates to be voted for at such election, to act as challenging committees, who are appointed and accredited by the executive or central committee of such political party or organization; any number of persons not exceeding three at a time from each of such political parties, appointed and accredited in the same manner as prescribed in subsection 2 for challenging committees, and any number of persons not exceeding three at a time appointed as observers under subsection 5, to witness the counting of ballots; any peace officer assigned or called upon to keep order or maintain compliance with the provisions of this chapter, upon request of the commissioner or of the chairperson of the precinct election board; one observer at a time representing any nonparty political organization, any candidate nominated by petition pursuant to chapter 45, or any other nonpartisan candidate in a city or school election, appearing on the ballot of the election in progress. Candidates who send observers to the polls shall provide each observer with a letter of appointment in the form prescribed by the state commissioner; any persons expressing an interest in a ballot issue to be voted upon at an election except a general or primary election. Any such person shall file a notice of intent to serve as an observer with the commissioner before election day. If more than three persons file a notice of intent to serve at the same time with respect to ballot issues at an election, the commissioner shall appoint from those submitting a notice of intent the three persons who may serve at that time as observers, and shall provide a schedule to all persons who filed notices of intent. The appointees, whenever possible, shall include both opponents and proponents of the ballot issues; any person authorized by the commissioner, in consultation with the secretary of state, for the purposes of conducting and attending educational voting programs for youth; reporters, photographers, and other staff representing the news media. (Iowa Code § 49.104)
Any person offering to vote may be challenged as unqualified by any precinct election official or registered voter. It is the duty of each official to challenge any person offering to vote whom the official knows or suspects is not duly qualified. (Iowa Code § 49.79).